diff --git a/platform/chromium/vapi-background.js b/platform/chromium/vapi-background.js
index 62b37f0cc1394..b8d19bc27de39 100644
--- a/platform/chromium/vapi-background.js
+++ b/platform/chromium/vapi-background.js
@@ -735,32 +735,21 @@ vAPI.messaging.listen = function(listenerName, callback) {
 
 vAPI.messaging.onPortMessage = (function() {
     var messaging = vAPI.messaging,
-        toAuxPending = new Map();
-
-    var supportsUserStylesheets = vAPI.supportsUserStylesheets;
+        supportsUserStylesheets = vAPI.supportsUserStylesheets;
 
     // Use a wrapper to avoid closure and to allow reuse.
-    var CallbackWrapper = function(port, request, timeout) {
+    var CallbackWrapper = function(port, request) {
         this.callback = this.proxy.bind(this); // bind once
-        this.init(port, request, timeout);
+        this.init(port, request);
     };
 
     CallbackWrapper.prototype = {
-        timerId: null,
-        init: function(port, request, timeout) {
+        init: function(port, request) {
             this.port = port;
             this.request = request;
-            if ( timeout !== undefined ) {
-                this.timerId = vAPI.setTimeout(this.callback, timeout);
-            }
             return this;
         },
         proxy: function(response) {
-            if ( this.timerId !== null ) {
-                clearTimeout(this.timerId);
-                toAuxPending.delete(this.timerId);
-                this.timerId = null;
-            }
             // https://github.com/chrisaljoudi/uBlock/issues/383
             if ( messaging.ports.has(this.port.name) ) {
                 this.port.postMessage({
@@ -777,67 +766,53 @@ vAPI.messaging.onPortMessage = (function() {
 
     var callbackWrapperJunkyard = [];
 
-    var callbackWrapperFactory = function(port, request, timeout) {
+    var callbackWrapperFactory = function(port, request) {
         var wrapper = callbackWrapperJunkyard.pop();
         if ( wrapper ) {
-            return wrapper.init(port, request, timeout);
-        }
-        return new CallbackWrapper(port, request, timeout);
-    };
-
-    var toAux = function(details, portFrom) {
-        var port, portTo,
-            chromiumTabId = toChromiumTabId(details.toTabId);
-
-        // TODO: This could be an issue with a lot of tabs: easy to address
-        //       with a port name to tab id map.
-        // When sending to an auxiliary process, the target is always the
-        // port associated with the root frame.
-        for ( var entry of messaging.ports ) {
-            port = entry[1];
-            if ( port.sender.frameId === 0 && port.sender.tab.id === chromiumTabId ) {
-                portTo = port;
-                break;
-            }
-        }
-
-        var wrapper;
-        if ( details.auxProcessId !== undefined ) {
-            wrapper = callbackWrapperFactory(portFrom, details, 1023);
+            return wrapper.init(port, request);
         }
-
-        // Destination not found: 
-        if ( portTo === undefined ) {
-            if ( wrapper !== undefined ) {
-                wrapper.callback();
-            }
-            return;
-        }
-
-        if ( wrapper !== undefined ) {
-            toAuxPending.set(wrapper.timerId, wrapper);
-        }
-
-        portTo.postMessage({
-            mainProcessId: wrapper && wrapper.timerId,
-            channelName: details.toChannel,
-            msg: details.msg
-        });
-    };
-
-    var toAuxResponse = function(details) {
-        var mainProcessId = details.mainProcessId;
-        if ( mainProcessId === undefined ) { return; }
-        var wrapper = toAuxPending.get(mainProcessId);
-        if ( wrapper === undefined ) { return; }
-        toAuxPending.delete(mainProcessId);
-        wrapper.callback(details.msg);
+        return new CallbackWrapper(port, request);
     };
 
-    var toFramework = function(msg, sender) {
-        var tabId = sender && sender.tab && sender.tab.id;
+    var toFramework = function(request, port) {
+        var sender = port && port.sender;
+        if ( !sender ) { return; }
+        var tabId = sender.tab && sender.tab.id;
         if ( !tabId ) { return; }
+        var msg = request.msg,
+            toPort;
         switch ( msg.what ) {
+        case 'connectionAccepted':
+        case 'connectionRefused':
+            toPort = messaging.ports.get(msg.fromToken);
+            if ( toPort !== undefined ) {
+                msg.tabId = tabId.toString();
+                toPort.postMessage(request);
+            } else {
+                msg.what = 'connectionBroken';
+                port.postMessage(request);
+            }
+            break;
+        case 'connectionRequested':
+            msg.tabId = '' + tabId.toString();
+            for ( toPort of messaging.ports.values() ) {
+                toPort.postMessage(request);
+            }
+            break;
+        case 'connectionBroken':
+        case 'connectionCheck':
+        case 'connectionMessage':
+            toPort = messaging.ports.get(
+                port.name === msg.fromToken ? msg.toToken : msg.fromToken
+            );
+            if ( toPort !== undefined ) {
+                msg.tabId = tabId.toString();
+                toPort.postMessage(request);
+            } else {
+                msg.what = 'connectionBroken';
+                port.postMessage(request);
+            }
+            break;
         case 'userCSS':
             var details = {
                 code: undefined,
@@ -863,23 +838,23 @@ vAPI.messaging.onPortMessage = (function() {
         }
     };
 
-    return function(request, port) {
-        // Auxiliary process to auxiliary process
-        if ( request.toTabId !== undefined ) {
-            toAux(request, port);
-            return;
-        }
-
-        // Auxiliary process to auxiliary process: response
-        if ( request.mainProcessId !== undefined ) {
-            toAuxResponse(request);
-            return;
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1392067
+    //   Workaround: manually remove ports matching removed tab.
+    chrome.tabs.onRemoved.addListener(function(tabId) {
+        for ( var port of messaging.ports.values() ) {
+            var tab = port.sender && port.sender.tab;
+            if ( !tab ) { continue; }
+            if ( tab.id === tabId ) {
+                vAPI.messaging.onPortDisconnect(port);
+            }
         }
+    });
 
+    return function(request, port) {
         // Content process to main process: framework handler.
         // No callback supported/needed for now.
-        if ( request.channelName === 'vapi-background' ) {
-            toFramework(request.msg, port.sender);
+        if ( request.channelName === 'vapi' ) {
+            toFramework(request, port);
             return;
         }
 
@@ -952,8 +927,8 @@ vAPI.messaging.broadcast = function(message) {
         broadcast: true,
         msg: message
     };
-    for ( var entry of this.ports ) {
-        entry[1].postMessage(messageWrapper);
+    for ( var port of this.ports.values() ) {
+        port.postMessage(messageWrapper);
     }
 };
 
diff --git a/platform/chromium/vapi-client.js b/platform/chromium/vapi-client.js
index 1cd30146c528b..0dfbd0dacf9ab 100644
--- a/platform/chromium/vapi-client.js
+++ b/platform/chromium/vapi-client.js
@@ -71,13 +71,35 @@ vAPI.messaging = {
     port: null,
     portTimer: null,
     portTimerDelay: 10000,
-    channels: Object.create(null),
-    channelCount: 0,
-    pending: Object.create(null),
-    pendingCount: 0,
+    channels: new Map(),
+    connections: new Map(),
+    pending: new Map(),
     auxProcessId: 1,
     shuttingDown: false,
 
+    Connection: function(handler, details) {
+        var messaging = vAPI.messaging;
+        this.messaging = messaging;
+        this.handler = handler;
+        this.id = details.id;
+        this.to = details.to;
+        this.toToken = details.toToken;
+        this.from = details.from;
+        this.fromToken = details.fromToken;
+        this.checkBound = this.check.bind(this);
+        this.checkTimer = undefined;
+        // On Firefox it appears ports are not automatically disconnected when
+        // navigating to another page.
+        if ( messaging.Connection.pagehide !== undefined ) { return; }
+        messaging.Connection.pagehide = function() {
+            for ( var connection of this.connections.values() ) {
+                connection.disconnect();
+                connection.handler(connection.toDetails('connectionBroken'));
+            }
+        }.bind(messaging);
+        window.addEventListener('pagehide', messaging.Connection.pagehide);
+    },
+
     shutdown: function() {
         this.shuttingDown = true;
         this.destroyPort();
@@ -87,46 +109,65 @@ vAPI.messaging = {
         this.port = null;
         vAPI.shutdown.exec();
     },
-    disconnectListenerCallback: null,
+    disconnectListenerBound: null,
 
     messageListener: function(details) {
-        if ( !details ) {
-            return;
-        }
+        if ( !details ) { return; }
 
         // Sent to all channels
-        if ( details.broadcast === true && !details.channelName ) {
-            for ( var channelName in this.channels ) {
+        if ( details.broadcast ) {
+            for ( var channelName of this.channels.keys() ) {
                 this.sendToChannelListeners(channelName, details.msg);
             }
             return;
         }
 
         // Response to specific message previously sent
+        var listener;
         if ( details.auxProcessId ) {
-            var listener = this.pending[details.auxProcessId];
-            delete this.pending[details.auxProcessId];
-            delete details.auxProcessId; // TODO: why?
-            if ( listener ) {
-                this.pendingCount -= 1;
+            listener = this.pending.get(details.auxProcessId);
+            if ( listener !== undefined ) {
+                this.pending.delete(details.auxProcessId);
                 listener(details.msg);
                 return;
             }
         }
 
-        // Sent to a specific channel
-        var response = this.sendToChannelListeners(details.channelName, details.msg);
-
-        // Respond back if required
-        if ( details.mainProcessId === undefined ) {
-            return;
-        }
-        var port = this.connect();
-        if ( port !== null ) {
-            port.postMessage({
-                mainProcessId: details.mainProcessId,
-                msg: response
-            });
+        if ( details.channelName !== 'vapi' ) { return; }
+
+        // Internal handler
+        var connection;
+
+        switch ( details.msg.what ) {
+        case 'connectionAccepted':
+        case 'connectionBroken':
+        case 'connectionCheck':
+        case 'connectionMessage':
+        case 'connectionRefused':
+            connection = this.connections.get(details.msg.id);
+            if ( connection === undefined ) { return; }
+            connection.receive(details.msg);
+            break;
+        case 'connectionRequested':
+            var listeners = this.channels.get(details.msg.to);
+            if ( listeners === undefined ) { return; }
+            var port = this.getPort();
+            if ( port === null ) { return; }
+            for ( listener of listeners ) {
+                if ( listener(details.msg) !== true ) { continue; }
+                details.msg.what = 'connectionAccepted';
+                details.msg.toToken = port.name;
+                connection = new this.Connection(listener, details.msg);
+                this.connections.set(connection.id, connection);
+                break;
+            }
+            if ( details.msg.what !== 'connectionAccepted' ) {
+                details.msg.what = 'connectionRefused';
+            }
+            port.postMessage(details);
+            break;
+        default:
+            break;
         }
     },
     messageListenerCallback: null,
@@ -135,15 +176,16 @@ vAPI.messaging = {
         this.portTimer = null;
         if (
             this.port !== null &&
-            this.channelCount === 0 &&
-            this.pendingCount === 0
+            this.channels.size === 0 &&
+            this.connections.size === 0 &&
+            this.pending.size === 0
         ) {
             return this.destroyPort();
         }
-        this.portTimer = vAPI.setTimeout(this.portPollerCallback, this.portTimerDelay);
+        this.portTimer = vAPI.setTimeout(this.portPollerBound, this.portTimerDelay);
         this.portTimerDelay = Math.min(this.portTimerDelay * 2, 60 * 60 * 1000);
     },
-    portPollerCallback: null,
+    portPollerBound: null,
 
     destroyPort: function() {
         if ( this.portTimer !== null ) {
@@ -154,20 +196,21 @@ vAPI.messaging = {
         if ( port !== null ) {
             port.disconnect();
             port.onMessage.removeListener(this.messageListenerCallback);
-            port.onDisconnect.removeListener(this.disconnectListenerCallback);
+            port.onDisconnect.removeListener(this.disconnectListenerBound);
             this.port = null;
         }
-        if ( this.channelCount !== 0 ) {
-            this.channels = Object.create(null);
-            this.channelCount = 0;
+        this.channels.clear();
+        if ( this.connections.size !== 0 ) {
+            for ( var connection of this.connections.values() ) {
+                connection.receive({ what: 'connectionBroken' });
+            }
+            this.connections.clear();
         }
         // service pending callbacks
-        if ( this.pendingCount !== 0 ) {
-            var pending = this.pending, callback;
-            this.pending = Object.create(null);
-            this.pendingCount = 0;
-            for ( var auxId in pending ) {
-                callback = pending[auxId];
+        if ( this.pending.size !== 0 ) {
+            var pending = this.pending;
+            this.pending = new Map();
+            for ( var callback of pending.values() ) {
                 if ( typeof callback === 'function' ) {
                     callback(null);
                 }
@@ -176,13 +219,11 @@ vAPI.messaging = {
     },
 
     createPort: function() {
-        if ( this.shuttingDown ) {
-            return null;
-        }
+        if ( this.shuttingDown ) { return null; }
         if ( this.messageListenerCallback === null ) {
             this.messageListenerCallback = this.messageListener.bind(this);
-            this.disconnectListenerCallback = this.disconnectListener.bind(this);
-            this.portPollerCallback = this.portPoller.bind(this);
+            this.disconnectListenerBound = this.disconnectListener.bind(this);
+            this.portPollerBound = this.portPoller.bind(this);
         }
         try {
             this.port = chrome.runtime.connect({name: vAPI.sessionId}) || null;
@@ -191,102 +232,109 @@ vAPI.messaging = {
         }
         if ( this.port !== null ) {
             this.port.onMessage.addListener(this.messageListenerCallback);
-            this.port.onDisconnect.addListener(this.disconnectListenerCallback);
-        }
-        this.portTimerDelay = 10000;
-        if ( this.portTimer === null ) {
-            this.portTimer = vAPI.setTimeout(this.portPollerCallback, this.portTimerDelay);
+            this.port.onDisconnect.addListener(this.disconnectListenerBound);
+            this.portTimerDelay = 10000;
+            if ( this.portTimer === null ) {
+                this.portTimer = vAPI.setTimeout(
+                    this.portPollerBound,
+                    this.portTimerDelay
+                );
+            }
         }
         return this.port;
     },
 
-    connect: function() {
+    getPort: function() {
         return this.port !== null ? this.port : this.createPort();
     },
 
     send: function(channelName, message, callback) {
-        this.sendTo(channelName, message, undefined, undefined, callback);
-    },
-
-    sendTo: function(channelName, message, toTabId, toChannel, callback) {
         // Too large a gap between the last request and the last response means
         // the main process is no longer reachable: memory leaks and bad
         // performance become a risk -- especially for long-lived, dynamic
         // pages. Guard against this.
-        if ( this.pendingCount > 25 ) {
+        if ( this.pending.size > 25 ) {
             vAPI.shutdown.exec();
         }
-        var port = this.connect();
+        var port = this.getPort();
         if ( port === null ) {
-            if ( typeof callback === 'function' ) {
-                callback();
-            }
+            if ( typeof callback === 'function' ) { callback(); }
             return;
         }
         var auxProcessId;
         if ( callback ) {
             auxProcessId = this.auxProcessId++;
-            this.pending[auxProcessId] = callback;
-            this.pendingCount += 1;
+            this.pending.set(auxProcessId, callback);
         }
         port.postMessage({
             channelName: channelName,
             auxProcessId: auxProcessId,
-            toTabId: toTabId,
-            toChannel: toChannel,
             msg: message
         });
     },
 
-    addChannelListener: function(channelName, callback) {
-        if ( typeof callback !== 'function' ) {
-            return;
-        }
-        var listeners = this.channels[channelName];
-        if ( listeners !== undefined && listeners.indexOf(callback) !== -1 ) {
-            console.error('Duplicate listener on channel "%s"', channelName);
-            return;
-        }
-        if ( listeners === undefined ) {
-            this.channels[channelName] = [callback];
-            this.channelCount += 1;
-        } else {
-            listeners.push(callback);
-        }
-        this.connect();
+    connectTo: function(from, to, handler) {
+        var port = this.getPort();
+        if ( port === null ) { return; }
+        var connection = new this.Connection(handler, {
+            id: from + '-' + to + '-' + vAPI.sessionId,
+            to: to,
+            from: from,
+            fromToken: port.name
+        });
+        this.connections.set(connection.id, connection);
+        port.postMessage({
+            channelName: 'vapi',
+            msg: {
+                what: 'connectionRequested',
+                id: connection.id,
+                from: from,
+                fromToken: port.name,
+                to: to
+            }
+        });
+        return connection.id;
     },
 
-    removeChannelListener: function(channelName, callback) {
-        if ( typeof callback !== 'function' ) {
-            return;
-        }
-        var listeners = this.channels[channelName];
+    disconnectFrom: function(connectionId) {
+        var connection = this.connections.get(connectionId);
+        if ( connection === undefined ) { return; }
+        connection.disconnect();
+    },
+
+    sendTo: function(connectionId, payload) {
+        var connection = this.connections.get(connectionId);
+        if ( connection === undefined ) { return; }
+        connection.send(payload);
+    },
+
+    addChannelListener: function(channelName, listener) {
+        var listeners = this.channels.get(channelName);
         if ( listeners === undefined ) {
-            return;
-        }
-        var pos = listeners.indexOf(callback);
-        if ( pos === -1 ) {
-            console.error('Listener not found on channel "%s"', channelName);
-            return;
+            this.channels.set(channelName, [ listener ]);
+        } else if ( listeners.indexOf(listener) === -1 ) {
+            listeners.push(listener);
         }
+        this.getPort();
+    },
+
+    removeChannelListener: function(channelName, listener) {
+        var listeners = this.channels.get(channelName);
+        if ( listeners === undefined ) { return; }
+        var pos = listeners.indexOf(listener);
+        if ( pos === -1 ) { return; }
         listeners.splice(pos, 1);
         if ( listeners.length === 0 ) {
-            delete this.channels[channelName];
-            this.channelCount -= 1;
+            this.channels.delete(channelName);
         }
     },
 
     removeAllChannelListeners: function(channelName) {
-        var listeners = this.channels[channelName];
-        if ( listeners === undefined ) {
-            return;
-        }
-        delete this.channels[channelName];
-        this.channelCount -= 1;
+        this.channels.delete(channelName);
     },
 
     sendToChannelListeners: function(channelName, msg) {
-        var listeners = this.channels[channelName];
+        var listeners = this.channels.get(channelName);
         if ( listeners === undefined ) { return; }
         listeners = listeners.slice(0);
         var response;
@@ -300,9 +348,94 @@ vAPI.messaging = {
 
 /******************************************************************************/
 
+vAPI.messaging.Connection.prototype = {
+    toDetails: function(what, payload) {
+        return {
+            what: what,
+            id: this.id,
+            from: this.from,
+            fromToken: this.fromToken,
+            to: this.to,
+            toToken: this.toToken,
+            payload: payload
+        };
+    },
+    disconnect: function() {
+        if ( this.checkTimer !== undefined ) {
+            clearTimeout(this.checkTimer);
+            this.checkTimer = undefined;
+        }
+        this.messaging.connections.delete(this.id);
+        var port = this.messaging.getPort();
+        if ( port === null ) { return; }
+        port.postMessage({
+            channelName: 'vapi',
+            msg:  this.toDetails('connectionBroken')
+        });
+    },
+    checkAsync: function() {
+        if ( this.checkTimer !== undefined ) {
+            clearTimeout(this.checkTimer);
+        }
+        this.checkTimer = vAPI.setTimeout(this.checkBound, 499);
+    },
+    check: function() {
+        this.checkTimer = undefined;
+        if ( this.messaging.connections.has(this.id) === false ) { return; }
+        var port = this.messaging.getPort();
+        if ( port === null ) { return; }
+        port.postMessage({
+            channelName: 'vapi',
+            msg: this.toDetails('connectionCheck')
+        });
+        this.checkAsync();
+    },
+    receive: function(details) {
+        switch ( details.what ) {
+        case 'connectionAccepted':
+            this.toToken = details.toToken;
+            this.handler(details);
+            this.checkAsync();
+            break;
+        case 'connectionBroken':
+            this.messaging.connections.delete(this.id);
+            this.handler(details);
+            break;
+        case 'connectionMessage':
+            this.handler(details);
+            this.checkAsync();
+            break;
+        case 'connectionCheck':
+            var port = this.messaging.getPort();
+            if ( port === null ) { return; }
+            if ( this.messaging.connections.has(this.id) ) {
+                this.checkAsync();
+            } else {
+                details.what = 'connectionBroken';
+                port.postMessage({ channelName: 'vapi', msg: details });
+            }
+            break;
+        case 'connectionRefused':
+            this.messaging.connections.delete(this.id);
+            this.handler(details);
+            break;
+        }
+    },
+    send: function(payload) {
+        var port = this.messaging.getPort();
+        if ( port === null ) { return; }
+        port.postMessage({
+            channelName: 'vapi',
+            msg: this.toDetails('connectionMessage', payload)
+        });
+    }
+};
+
+/******************************************************************************/
+
 vAPI.shutdown.add(function() {
     vAPI.messaging.shutdown();
-    delete window.vAPI;
+    window.vAPI = undefined;
 });
 
 // https://www.youtube.com/watch?v=rT5zCHn0tsg
diff --git a/platform/firefox/vapi-background.js b/platform/firefox/vapi-background.js
index 40157849fc883..c3579826e72df 100644
--- a/platform/firefox/vapi-background.js
+++ b/platform/firefox/vapi-background.js
@@ -1572,31 +1572,22 @@ vAPI.messaging.listen = function(listenerName, callback) {
 
 vAPI.messaging.onMessage = (function() {
     var messaging = vAPI.messaging;
-    var toAuxPending = {};
 
     // Use a wrapper to avoid closure and to allow reuse.
-    var CallbackWrapper = function(messageManager, listenerId, channelName, auxProcessId, timeout) {
+    var CallbackWrapper = function(messageManager, listenerId, channelName, auxProcessId) {
         this.callback = this.proxy.bind(this); // bind once
-        this.init(messageManager, listenerId, channelName, auxProcessId, timeout);
+        this.init(messageManager, listenerId, channelName, auxProcessId);
     };
 
-    CallbackWrapper.prototype.init = function(messageManager, listenerId, channelName, auxProcessId, timeout) {
+    CallbackWrapper.prototype.init = function(messageManager, listenerId, channelName, auxProcessId) {
         this.messageManager = messageManager;
         this.listenerId = listenerId;
         this.channelName = channelName;
         this.auxProcessId = auxProcessId;
-        this.timerId = timeout !== undefined ?
-                            vAPI.setTimeout(this.callback, timeout) :
-                            null;
         return this;
     };
 
     CallbackWrapper.prototype.proxy = function(response) {
-        if ( this.timerId !== null ) {
-            clearTimeout(this.timerId);
-            delete toAuxPending[this.timerId];
-            this.timerId = null;
-        }
         var message = JSON.stringify({
             auxProcessId: this.auxProcessId,
             channelName: this.channelName,
@@ -1619,97 +1610,15 @@ vAPI.messaging.onMessage = (function() {
 
     var callbackWrapperJunkyard = [];
 
-    var callbackWrapperFactory = function(messageManager, listenerId, channelName, auxProcessId, timeout) {
+    var callbackWrapperFactory = function(messageManager, listenerId, channelName, auxProcessId) {
         var wrapper = callbackWrapperJunkyard.pop();
         if ( wrapper ) {
-            return wrapper.init(messageManager, listenerId, channelName, auxProcessId, timeout);
+            return wrapper.init(messageManager, listenerId, channelName, auxProcessId);
         }
-        return new CallbackWrapper(messageManager, listenerId, channelName, auxProcessId, timeout);
-    };
-
-    // "Auxiliary process": any process other than main process.
-    var toAux = function(target, details) {
-        var messageManagerFrom = target.messageManager;
-
-        // Message came from a popup, and its message manager is not usable.
-        // So instead we broadcast to the parent window.
-        if ( !messageManagerFrom ) {
-            messageManagerFrom = getOwnerWindow(
-                target.webNavigation.QueryInterface(Ci.nsIDocShell).chromeEventHandler
-            ).messageManager;
-        }
-
-        var wrapper;
-        if ( details.auxProcessId !== undefined ) {
-            var channelNameRaw = details.channelName;
-            var pos = channelNameRaw.indexOf('|');
-            wrapper = callbackWrapperFactory(
-                messageManagerFrom,
-                channelNameRaw.slice(0, pos),
-                channelNameRaw.slice(pos + 1),
-                details.auxProcessId,
-                1023
-            );
-        }
-
-        var messageManagerTo = null;
-        var browser = tabWatcher.browserFromTabId(details.toTabId);
-        if ( browser !== null && browser.messageManager ) {
-            messageManagerTo = browser.messageManager;
-        }
-        if ( messageManagerTo === null ) {
-            if ( wrapper !== undefined ) {
-                wrapper.callback();
-            }
-            return;
-        }
-
-        // As per HTML5, timer id is always an integer, thus suitable to be used
-        // as a key, and which value is safe to use across process boundaries.
-        if ( wrapper !== undefined ) {
-            toAuxPending[wrapper.timerId] = wrapper;
-        }
-
-        var targetId = location.host + ':broadcast';
-        var payload = JSON.stringify({
-            mainProcessId: wrapper && wrapper.timerId,
-            channelName: details.toChannel,
-            msg: details.msg
-        });
-
-        if ( messageManagerTo.sendAsyncMessage ) {
-            messageManagerTo.sendAsyncMessage(targetId, payload);
-        } else {
-            messageManagerTo.broadcastAsyncMessage(targetId, payload);
-        }
-    };
-
-    var toAuxResponse = function(details) {
-        var mainProcessId = details.mainProcessId;
-        if ( mainProcessId === undefined ) {
-            return;
-        }
-        if ( toAuxPending.hasOwnProperty(mainProcessId) === false ) {
-            return;
-        }
-        var wrapper = toAuxPending[mainProcessId];
-        delete toAuxPending[mainProcessId];
-        wrapper.callback(details.msg);
+        return new CallbackWrapper(messageManager, listenerId, channelName, auxProcessId);
     };
 
     return function({target, data}) {
-        // Auxiliary process to auxiliary process
-        if ( data.toTabId !== undefined ) {
-            toAux(target, data);
-            return;
-        }
-
-        // Auxiliary process to auxiliary process: response
-        if ( data.mainProcessId !== undefined ) {
-            toAuxResponse(data);
-            return;
-        }
-
         // Auxiliary process to main process
         var messageManager = target.messageManager;
 
@@ -1748,15 +1657,11 @@ vAPI.messaging.onMessage = (function() {
         if ( typeof listener === 'function' ) {
             r = listener(data.msg, sender, callback);
         }
-        if ( r !== messaging.UNHANDLED ) {
-            return;
-        }
+        if ( r !== messaging.UNHANDLED ) { return; }
 
         // Auxiliary process to main process: default handler
         r = messaging.defaultHandler(data.msg, sender, callback);
-        if ( r !== messaging.UNHANDLED ) {
-            return;
-        }
+        if ( r !== messaging.UNHANDLED ) { return; }
 
         // Auxiliary process to main process: no handler
         console.error('uBlock> messaging > unknown request: %o', data);
diff --git a/platform/firefox/vapi-client.js b/platform/firefox/vapi-client.js
index d30bbe631ac6d..aeb83cd193a22 100644
--- a/platform/firefox/vapi-client.js
+++ b/platform/firefox/vapi-client.js
@@ -150,22 +150,18 @@ var processUserCSS = function(details, callback) {
 /******************************************************************************/
 
 vAPI.messaging = {
-    channels: Object.create(null),
-    channelCount: 0,
-    pending: Object.create(null),
-    pendingCount: 0,
+    channels: new Map(),
+    pending: new Map(),
     auxProcessId: 1,
     connected: false,
 
     messageListener: function(msg) {
         var details = JSON.parse(msg);
-        if ( !details ) {
-            return;
-        }
+        if ( !details ) { return; }
 
         // Sent to all channels
         if ( details.broadcast && !details.channelName ) {
-            for ( var channelName in this.channels ) {
+            for ( var channelName of this.channels.keys() ) {
                 this.sendToChannelListeners(channelName, details.msg);
             }
             return;
@@ -173,42 +169,27 @@ vAPI.messaging = {
 
         // Response to specific message previously sent
         if ( details.auxProcessId ) {
-            var listener = this.pending[details.auxProcessId];
-            delete this.pending[details.auxProcessId];
-            delete details.auxProcessId; // TODO: why?
+            var listener = this.pending.get(details.auxProcessId);
+            this.pending.delete(details.auxProcessId);
             if ( listener ) {
-                this.pendingCount -= 1;
                 listener(details.msg);
                 return;
             }
         }
 
         // Sent to a specific channel
-        var response = this.sendToChannelListeners(details.channelName, details.msg);
-
-        // Respond back if required
-        if ( details.mainProcessId === undefined ) {
-            return;
-        }
-        sendAsyncMessage('ublock0:background', {
-            mainProcessId: details.mainProcessId,
-            msg: response
-        });
+        this.sendToChannelListeners(details.channelName, details.msg);
     },
 
     builtinListener: function(msg) {
         if ( msg.cmd === 'injectScript' ) {
             // injectScript is not always present.
             // - See contentObserver.initContentScripts in frameModule.js
-            if ( typeof self.injectScript !== 'function' )  {
-                return;
-            }
+            if ( typeof self.injectScript !== 'function' )  { return; }
             var details = msg.details;
             // Whether to inject in all child frames. Default to only top frame.
             var allFrames = details.allFrames || false;
-            if ( allFrames !== true && window !== window.top ) {
-                return;
-            }
+            if ( allFrames !== true && window !== window.top ) { return; }
             // https://github.com/gorhill/uBlock/issues/876
             // Enforce `details.runAt`. Default to `document_end`.
             var runAt = details.runAt || 'document_end';
@@ -225,7 +206,7 @@ vAPI.messaging = {
         }
         if ( msg.cmd === 'shutdownSandbox' ) {
             vAPI.shutdown.exec();
-            this.stop();
+            vAPI.messaging.stop();
             if ( typeof self.outerShutdown === 'function' ) {
                 outerShutdown();
             }
@@ -263,7 +244,7 @@ vAPI.messaging = {
     toggleListenerCallback: null,
 
     start: function() {
-        this.addChannelListener('vAPI', this.builtinListener.bind(this));
+        this.addChannelListener('vAPI', this.builtinListener);
         if ( this.toggleListenerCallback === null ) {
             this.toggleListenerCallback = this.toggleListener.bind(this);
         }
@@ -277,14 +258,11 @@ vAPI.messaging = {
             window.removeEventListener('pageshow', this.toggleListenerCallback, true);
         }
         this.disconnect();
-        this.channels = Object.create(null);
-        this.channelCount = 0;
+        this.channels.clear();
         // service pending callbacks
-        var pending = this.pending, callback;
-        this.pending = Object.create(null);
-        this.pendingCount = 0;
-        for ( var auxId in pending ) {
-            callback = pending[auxId];
+        var pending = this.pending;
+        this.pending = new Map();
+        for ( var callback of pending.values() ) {
             if ( typeof callback === 'function' ) {
                 callback(null);
             }
@@ -307,17 +285,11 @@ vAPI.messaging = {
 
     send: function(channelName, message, callback) {
         // User stylesheets are handled content-side on legacy Firefox.
-        if ( channelName === 'vapi-background' && message.what === 'userCSS' ) {
+        if ( channelName === 'vapi' && message.what === 'userCSS' ) {
             return processUserCSS(message, callback);
         }
-        this.sendTo(channelName, message, undefined, undefined, callback);
-    },
-
-    sendTo: function(channelName, message, toTabId, toChannel, callback) {
         if ( !this.connected ) {
-            if ( typeof callback === 'function' ) {
-                callback();
-            }
+            if ( typeof callback === 'function' ) { callback(); }
             return;
         }
         // Too large a gap between the last request and the last response means
@@ -331,67 +303,57 @@ vAPI.messaging = {
         var auxProcessId;
         if ( callback ) {
             auxProcessId = this.auxProcessId++;
-            this.pending[auxProcessId] = callback;
-            this.pendingCount += 1;
+            this.pending.set(auxProcessId, callback);
         }
         sendAsyncMessage('ublock0:background', {
             channelName: self._sandboxId_ + '|' + channelName,
             auxProcessId: auxProcessId,
-            toTabId: toTabId,
-            toChannel: toChannel,
             msg: message
         });
     },
 
-    addChannelListener: function(channelName, callback) {
-        if ( typeof callback !== 'function' ) {
-            return;
-        }
-        var listeners = this.channels[channelName];
-        if ( listeners !== undefined && listeners.indexOf(callback) !== -1 ) {
-            console.error('Duplicate listener on channel "%s"', channelName);
-            return;
-        }
+    // TODO: implement as time permits.
+    connectTo: function(from, to, handler) {
+        handler({
+            what: 'connectionRefused',
+            from: from,
+            to: to
+        });
+    },
+
+    disconnectFrom: function() {
+    },
+
+    sendTo: function() {
+    },
+
+    addChannelListener: function(channelName, listener) {
+        var listeners = this.channels.get(channelName);
         if ( listeners === undefined ) {
-            this.channels[channelName] = [callback];
-            this.channelCount += 1;
-        } else {
-            listeners.push(callback);
+            this.channels.set(channelName, [ listener ]);
+        } else if ( listeners.indexOf(listener) === -1 ) {
+            listeners.push(listener);
         }
         this.connect();
     },
 
-    removeChannelListener: function(channelName, callback) {
-        if ( typeof callback !== 'function' ) {
-            return;
-        }
-        var listeners = this.channels[channelName];
-        if ( listeners === undefined ) {
-            return;
-        }
-        var pos = this.listeners.indexOf(callback);
-        if ( pos === -1 ) {
-            console.error('Listener not found on channel "%s"', channelName);
-            return;
-        }
+    removeChannelListener: function(channelName, listener) {
+        var listeners = this.channels.get(channelName);
+        if ( listeners === undefined ) { return; }
+        var pos = this.listeners.indexOf(listener);
+        if ( pos === -1 ) { return; }
         listeners.splice(pos, 1);
         if ( listeners.length === 0 ) {
-            delete this.channels[channelName];
-            this.channelCount -= 1;
+            this.channels.delete(channelName);
         }
     },
 
     removeAllChannelListeners: function(channelName) {
-        var listeners = this.channels[channelName];
-        if ( listeners === undefined ) {
-            return;
-        }
-        delete this.channels[channelName];
-        this.channelCount -= 1;
+        this.channels.delete(channelName);
     },
 
     sendToChannelListeners: function(channelName, msg) {
-        var listeners = this.channels[channelName];
+        var listeners = this.channels.get(channelName);
         if ( listeners === undefined ) { return; }
         listeners = listeners.slice(0);
         var response;
diff --git a/platform/webext/vapi-usercss.js b/platform/webext/vapi-usercss.js
index b8199d99be3c2..2483baba55ee4 100644
--- a/platform/webext/vapi-usercss.js
+++ b/platform/webext/vapi-usercss.js
@@ -33,7 +33,7 @@ vAPI.userStylesheet = {
     removed: new Set(),
     apply: function() {
         if ( this.added.size === 0 && this.removed.size === 0 ) { return; }
-        vAPI.messaging.send('vapi-background', {
+        vAPI.messaging.send('vapi', {
             what: 'userCSS',
             add: Array.from(this.added),
             remove: Array.from(this.removed)
diff --git a/src/css/logger-ui-inspector.css b/src/css/logger-ui-inspector.css
index 420df1bb6d423..2c24aba8b4738 100644
--- a/src/css/logger-ui-inspector.css
+++ b/src/css/logger-ui-inspector.css
@@ -28,16 +28,23 @@
     background-color: #fee;
     }
 #domInspector li > * {
+    font-size: 0.8rem;
+    display: inline-block;
+    line-height: 1.2;
     margin-right: 1em;
+    vertical-align: middle;
+    }
+#domInspector li > span {
+    color: #aaa;
     }
 #domInspector li > span:first-child {
     color: #000;
     cursor: default;
-    display: inline-block;
+    font-size: 1rem;
     margin-right: 0;
     opacity: 0.5;
+    padding: 0 4px 0 1px;
     visibility: hidden;
-    width: 1em;
     }
 #domInspector li > span:first-child:hover {
     opacity: 1;
@@ -54,30 +61,51 @@
     }
 #domInspector li.branch.show > span:first-child:before {
     content: '\25be';
-    visibility: visible;
     }
 #domInspector li.branch.hasCosmeticHide > span:first-child:before {
     color: red;
     }
 #domInspector li > code {
     cursor: pointer;
-    font: 12px/1.4 monospace;
+    font-family: monospace;
+    overflow: hidden;
+    text-overflow: ellipsis;
     }
 #domInspector li > code.off {
     text-decoration: line-through;
     }
-#domInspector li > span {
-    color: #aaa;
-    }
 #domInspector li > code.filter {
     color: red;
     }
+
 #domInspector li > ul {
+    display: block;
+    }
+#domInspector li:not(.hasCosmeticHide):not(.isCosmeticHide):not(.show) > ul {
     display: none;
     }
-#domInspector li.show > ul {
+
+#domInspector.vCompact li:not(.hasCosmeticHide):not(.isCosmeticHide) {
+    display: none;
+    }
+#domInspector #domTree > li {
+    display: block;
+    }
+#domInspector.vCompact ul {
+    display: block;
+    }
+#domInspector li > ul > li:not(.hasCosmeticHide):not(.isCosmeticHide) {
+    display: none;
+    }
+#domInspector li.show > ul > li:not(.hasCosmeticHide):not(.isCosmeticHide) {
     display: block;
     }
+#domInspector li:not(.hasCosmeticHide):not(.isCosmeticHide) {
+    display: block;
+    }
+#domInspector.hCompact li > code:first-of-type {
+    max-width: 12em;
+    }
 
 #cosmeticFilteringDialog .dialog {
     text-align: center;
diff --git a/src/css/logger-ui.css b/src/css/logger-ui.css
index 355c2f11e8430..e0c078a9d3679 100644
--- a/src/css/logger-ui.css
+++ b/src/css/logger-ui.css
@@ -60,6 +60,7 @@ textarea {
 
 #inspectors {
     bottom: 0;
+    font: 13px sans-serif;
     position: absolute;
     top: 0;
     width: 100%;
@@ -80,18 +81,22 @@ textarea {
     width: 100%;
 }
 
-#netInspector {
-    font: 13px sans-serif;
-    }
-#inspectors.dom #netInspector {
-    display: none;
-    }
-#netInspector #compactViewToggler.button:before {
+.vCompactToggler.button:before {
     content: '\f102';
     }
-#netInspector.compactView #compactViewToggler.button:before {
+.vCompact .vCompactToggler.button:before {
     content: '\f103';
     }
+.hCompactToggler.button:before {
+    content: '\f100';
+    }
+.hCompact .hCompactToggler.button:before {
+    content: '\f101';
+    }
+
+#inspectors.dom #netInspector {
+    display: none;
+    }
 #netInspector #filterButton {
     opacity: 0.25;
     }
@@ -190,7 +195,7 @@ body #netInspector td {
 #netInspector tr td:last-of-type {
     border-right: none;
     }
-#netInspector.compactView td {
+#netInspector.vCompact td {
     overflow: hidden;
     text-overflow: ellipsis;
     white-space: nowrap;
diff --git a/src/js/logger-ui-inspector.js b/src/js/logger-ui-inspector.js
index 57f358d36082b..f598ec2db293b 100644
--- a/src/js/logger-ui-inspector.js
+++ b/src/js/logger-ui-inspector.js
@@ -32,7 +32,11 @@
 var showdomButton = uDom.nodeFromId('showdom');
 
 // Don't bother if the browser is not modern enough.
-if ( typeof Map === 'undefined' || Map.polyfill || typeof WeakMap === 'undefined' ) {
+if (
+    typeof Map === 'undefined' ||
+    Map.polyfill ||
+    typeof WeakMap === 'undefined'
+) {
     showdomButton.classList.add('disabled');
     return;
 }
@@ -40,13 +44,10 @@ if ( typeof Map === 'undefined' || Map.polyfill || typeof WeakMap === 'undefined
 /******************************************************************************/
 
 var logger = self.logger;
-var messaging = vAPI.messaging;
-
+var inspectorConnectionId;
 var inspectedTabId = '';
 var inspectedURL = '';
 var inspectedHostname = '';
-var pollTimer = null;
-var fingerprint = null;
 var inspector = uDom.nodeFromId('domInspector');
 var domTree = uDom.nodeFromId('domTree');
 var tabSelector = uDom.nodeFromId('pageSelector');
@@ -55,13 +56,45 @@ var filterToIdMap = new Map();
 
 /******************************************************************************/
 
+var messaging = vAPI.messaging;
+
+messaging.addChannelListener('loggerUI', function(msg) {
+    switch ( msg.what ) {
+    case 'connectionBroken':
+        if ( inspectorConnectionId === msg.id ) {
+            filterToIdMap.clear();
+            logger.removeAllChildren(domTree);
+            inspectorConnectionId = undefined;
+        }
+        injectInspector();
+        break;
+    case 'connectionMessage':
+        if ( msg.payload.what === 'domLayoutFull' ) {
+            inspectedURL = msg.payload.url;
+            inspectedHostname = msg.payload.hostname;
+            renderDOMFull(msg.payload);
+        } else if ( msg.payload.what === 'domLayoutIncremental' ) {
+            renderDOMIncremental(msg.payload);
+        }
+        break;
+    case 'connectionRequested':
+        if ( msg.from !== 'domInspector' ) { return false; }
+        if ( msg.tabId !== inspectedTabId ) { return false; }
+        filterToIdMap.clear();
+        logger.removeAllChildren(domTree);
+        inspectorConnectionId = msg.id;
+        return true;
+    }
+});
+
+/******************************************************************************/
+
 var nodeFromDomEntry = function(entry) {
     var node, value;
     var li = document.createElement('li');
     li.setAttribute('id', entry.nid);
     // expander/collapser
-    node = document.createElement('span');
-    li.appendChild(node);
+    li.appendChild(document.createElement('span'));
     // selector
     node = document.createElement('code');
     node.textContent = entry.sel;
@@ -190,16 +223,14 @@ var renderDOMIncremental = function(response) {
     //  1 = node added
     // -1 = node removed
     var journal = response.journal;
-    var nodes = response.nodes;
+    var nodes = new Map(response.nodes);
     var entry, previous, li, ul;
     for ( var i = 0, n = journal.length; i < n; i++ ) {
         entry = journal[i];
         // Remove node
         if ( entry.what === -1 ) {
             li = document.getElementById(entry.nid);
-            if ( li === null ) {
-                continue;
-            }
+            if ( li === null ) { continue; }
             patchIncremental(li, -1);
             li.parentNode.removeChild(li);
             continue;
@@ -218,7 +249,7 @@ var renderDOMIncremental = function(response) {
                 continue;
             }
             ul = previous.parentElement;
-            li = nodeFromDomEntry(nodes[entry.nid]);
+            li = nodeFromDomEntry(nodes.get(entry.nid));
             ul.insertBefore(li, previous.nextElementSibling);
             patchIncremental(li, 1);
             continue;
@@ -237,7 +268,7 @@ var renderDOMIncremental = function(response) {
                 li.appendChild(ul);
                 li.classList.add('branch');
             }
-            li = nodeFromDomEntry(nodes[entry.nid]);
+            li = nodeFromDomEntry(nodes.get(entry.nid));
             ul.appendChild(li);
             patchIncremental(li, 1);
             continue;
@@ -350,7 +381,7 @@ var startDialog = (function() {
         };
     })();
 
-    var onClick = function(ev) {
+    var onClicked = function(ev) {
         var target = ev.target;
 
         // click outside the dialog proper
@@ -367,83 +398,51 @@ var startDialog = (function() {
         }
     };
 
-    var onCooked = function(entries) {
-        if ( Array.isArray(entries) === false ) {
-            return;
+    var showCommitted = function() {
+        messaging.sendTo(inspectorConnectionId, {
+            what: 'showCommitted',
+            hide: hideSelectors.join(',\n'),
+            unhide: unhideSelectors.join(',\n')
+        });
+    };
+
+    var showInteractive = function() {
+        messaging.sendTo(inspectorConnectionId, {
+            what: 'showInteractive',
+            hide: hideSelectors.join(',\n'),
+            unhide: unhideSelectors.join(',\n')
+        });
+    };
+
+    var start = function() {
+        hideSelectors = [];
+        textarea.addEventListener('input', onInputChanged);
+        var node;
+        for ( node of domTree.querySelectorAll('code.off') ) {
+            if ( node.classList.contains('filter') === false ) {
+                hideSelectors.push(selectorFromNode(node));
+            }
         }
-        hideSelectors = entries;
-        var taValue = [], i, node;
+        var taValue = [];
         var d = new Date();
         taValue.push('! ' + d.toLocaleString() + ' ' + inspectedURL);
-        for ( i = 0; i < entries.length; i++ ) {
-            taValue.push(inspectedHostname + '##' + entries[i]);
+        for ( var selector of hideSelectors ) {
+            taValue.push(inspectedHostname + '##' + selector);
         }
         var ids = new Set(), id;
-        var nodes = domTree.querySelectorAll('code.filter.off');
-        for ( i = 0; i < nodes.length; i++ ) {
-            node = nodes[i];
+        for ( node of domTree.querySelectorAll('code.filter.off') ) {
             id = node.getAttribute('data-filter-id');
-            if ( ids.has(id) ) {
-                continue;
-            }
+            if ( ids.has(id) ) { continue; }
             ids.add(id);
             unhideSelectors.push(node.textContent);
             taValue.push(inspectedHostname + '#@#' + node.textContent);
         }
         textarea.value = taValue.join('\n');
         document.body.appendChild(dialog);
-        dialog.addEventListener('click', onClick, true);
+        dialog.addEventListener('click', onClicked, true);
         showCommitted();
     };
 
-    var showCommitted = function() {
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'showCommitted',
-                hide: hideSelectors.join(',\n'),
-                unhide: unhideSelectors.join(',\n')
-            },
-            inspectedTabId,
-            'domInspector'
-        );
-    };
-
-    var showInteractive = function() {
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'showInteractive',
-                hide: hideSelectors.join(',\n'),
-                unhide: unhideSelectors.join(',\n')
-            },
-            inspectedTabId,
-            'domInspector'
-        );
-    };
-
-    var start = function() {
-        textarea.addEventListener('input', onInputChanged);
-        var node, entries = [];
-        var nodes = domTree.querySelectorAll('code.off');
-        for ( var i = 0; i < nodes.length; i++ ) {
-            node = nodes[i];
-            if ( node.classList.contains('filter') === false ) {
-                entries.push({
-                    nid: nidFromNode(node),
-                    selector: selectorFromNode(node)
-                });
-            }
-        }
-        messaging.sendTo(
-            'loggerUI',
-            { what: 'cookFilters', entries: entries },
-            inspectedTabId,
-            'domInspector',
-            onCooked
-        );
-    };
-
     var stop = function() {
         if ( inputTimer !== null ) {
             clearTimeout(inputTimer);
@@ -453,7 +452,7 @@ var startDialog = (function() {
         hideSelectors = [];
         unhideSelectors = [];
         textarea.removeEventListener('input', onInputChanged);
-        dialog.removeEventListener('click', onClick, true);
+        dialog.removeEventListener('click', onClicked, true);
         document.body.removeChild(dialog);
     };
 
@@ -462,12 +461,10 @@ var startDialog = (function() {
 
 /******************************************************************************/
 
-var onClick = function(ev) {
+var onClicked = function(ev) {
     ev.stopPropagation();
 
-    if ( inspectedTabId === '' ) {
-        return;
-    }
+    if ( inspectedTabId === '' ) { return; }
 
     var target = ev.target;
     var parent = target.parentElement;
@@ -479,30 +476,28 @@ var onClick = function(ev) {
         parent.classList.contains('branch') &&
         target === parent.firstElementChild
     ) {
-        target.parentElement.classList.toggle('show');
+        var state = parent.classList.toggle('show');
+        if ( !state ) {
+            for ( var node of parent.querySelectorAll('.branch') ) {
+                node.classList.remove('show');
+            }
+        }
         return;
     }
 
     // Not a node or filter 
-    if ( target.localName !== 'code' ) {
-        return;
-    }
+    if ( target.localName !== 'code' ) { return; }
 
     // Toggle cosmetic filter
     if ( target.classList.contains('filter') ) {
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'toggleFilter',
-                original: false,
-                target: target.classList.toggle('off'),
-                selector: selectorFromNode(target),
-                filter: selectorFromFilter(target),
-                nid: ''
-            },
-            inspectedTabId,
-            'domInspector'
-        );
+        messaging.sendTo(inspectorConnectionId, {
+            what: 'toggleFilter',
+            original: false,
+            target: target.classList.toggle('off'),
+            selector: selectorFromNode(target),
+            filter: selectorFromFilter(target),
+            nid: nidFromNode(target)
+        });
         uDom('[data-filter-id="' + target.getAttribute('data-filter-id') + '"]', inspector).toggleClass(
             'off',
             target.classList.contains('off')
@@ -510,18 +505,13 @@ var onClick = function(ev) {
     }
     // Toggle node
     else {
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'toggleNodes',
-                original: true,
-                target: target.classList.toggle('off') === false,
-                selector: selectorFromNode(target),
-                nid: nidFromNode(target)
-            },
-            inspectedTabId,
-            'domInspector'
-        );
+        messaging.sendTo(inspectorConnectionId, {
+            what: 'toggleNodes',
+            original: true,
+            target: target.classList.toggle('off') === false,
+            selector: selectorFromNode(target),
+            nid: nidFromNode(target)
+        });
     }
 
     var cantCreate = domTree.querySelector('.off') === null;
@@ -537,38 +527,25 @@ var onMouseOver = (function() {
 
     var timerHandler = function() {
         mouseoverTimer = null;
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'highlightOne',
-                selector: selectorFromNode(mouseoverTarget),
-                nid: nidFromNode(mouseoverTarget),
-                scrollTo: true
-            },
-            inspectedTabId,
-            'domInspector'
-        );
+        messaging.sendTo(inspectorConnectionId, {
+            what: 'highlightOne',
+            selector: selectorFromNode(mouseoverTarget),
+            nid: nidFromNode(mouseoverTarget),
+            scrollTo: true
+        });
     };
 
     return function(ev) {
-        if ( inspectedTabId === '' ) {
-            return;
-        }
+        if ( inspectedTabId === '' ) { return; }
         // Convenience: skip real-time highlighting if shift key is pressed.
-        if ( ev.shiftKey ) {
-            return;
-        }
+        if ( ev.shiftKey ) { return; }
         // Find closest `li`
         var target = ev.target;
         while ( target !== null ) {
-            if ( target.localName === 'li' ) {
-                break;
-            }
+            if ( target.localName === 'li' ) { break; }
             target = target.parentElement;
         }
-        if ( target === mouseoverTarget ) {
-            return;
-        }
+        if ( target === mouseoverTarget ) { return; }
         mouseoverTarget = target;
         if ( mouseoverTimer === null ) {
             mouseoverTimer = vAPI.setTimeout(timerHandler, 50);
@@ -579,121 +556,33 @@ var onMouseOver = (function() {
 /******************************************************************************/
 
 var currentTabId = function() {
-    if ( showdomButton.classList.contains('active') === false ) {
-        return '';
-    }
+    if ( showdomButton.classList.contains('active') === false ) { return ''; }
     var tabId = logger.tabIdFromClassName(tabSelector.value) || '';
     return tabId !== 'bts' ? tabId : '';
 };
 
 /******************************************************************************/
 
-var fetchDOMAsync = (function() {
-    var onFetched = function(response) {
-        if ( !response || currentTabId() !== inspectedTabId ) {
-            shutdownInspector();
-            injectInspectorAsync(250);
-            return;
-        }
-
-        switch ( response.status ) {
-        case 'full':
-            renderDOMFull(response);
-            fingerprint = response.fingerprint;
-            inspectedURL = response.url;
-            inspectedHostname = response.hostname;
-            break;
-
-        case 'incremental':
-            renderDOMIncremental(response);
-            break;
-
-        case 'nochange':
-        case 'busy':
-            break;
-
-        default:
-            break;
-        }
-
-        fetchDOMAsync();
-    };
-
-    var onTimeout = function() {
-        pollTimer = null;
-        messaging.sendTo(
-            'loggerUI',
-            {
-                what: 'domLayout',
-                fingerprint: fingerprint
-            },
-            inspectedTabId,
-            'domInspector',
-            onFetched
-        );
-    };
-
-    // Poll for DOM layout data every ~2 seconds at most
-    return function(delay) {
-        if ( pollTimer === null ) {
-            pollTimer = vAPI.setTimeout(onTimeout, delay || 2003);
-        }
-    };
-})();
-
-/******************************************************************************/
-
 var injectInspector = function() {
     var tabId = currentTabId();
-    // No valid tab, go back
-    if ( tabId === '' ) {
-        injectInspectorAsync();
-        return;
-    }
+    if ( tabId === '' ) { return; }
     inspectedTabId = tabId;
-    fingerprint = null;
-    messaging.send(
-        'loggerUI',
-        {
-            what: 'scriptlet',
-            tabId: tabId,
-            scriptlet: 'dom-inspector'
-        }
-    );
-    fetchDOMAsync(250);
-};
-
-/******************************************************************************/
-
-var injectInspectorAsync = function(delay) {
-    if ( pollTimer !== null ) {
-        return;
-    }
-    if ( showdomButton.classList.contains('active') === false ) {
-        return;
-    }
-    pollTimer = vAPI.setTimeout(function() {
-        pollTimer = null;
-        injectInspector();
-    }, delay || 1001);
+    messaging.send('loggerUI', {
+        what: 'scriptlet',
+        tabId: tabId,
+        scriptlet: 'dom-inspector'
+    });
 };
 
 /******************************************************************************/
 
 var shutdownInspector = function() {
-    if ( inspectedTabId !== '' ) {
-        messaging.sendTo(
-            'loggerUI',
-            { what: 'shutdown' },
-            inspectedTabId,
-            'domInspector'
-        );
+    if ( inspectorConnectionId !== undefined ) {
+        messaging.disconnectFrom(inspectorConnectionId);
+        inspectorConnectionId = undefined;
     }
     logger.removeAllChildren(domTree);
-    if ( pollTimer !== null ) {
-        clearTimeout(pollTimer);
-        pollTimer = null;
-    }
+    inspector.classList.add('vCompact');
     inspectedTabId = '';
 };
 
@@ -702,34 +591,38 @@ var shutdownInspector = function() {
 var onTabIdChanged = function() {
     if ( inspectedTabId !== currentTabId() ) {
         shutdownInspector();
-        injectInspectorAsync(250);
+        injectInspector();
+    }
+};
+
+/******************************************************************************/
+
+var toggleVCompactView = function() {
+    var state = !inspector.classList.toggle('vCompact');
+    var branches = document.querySelectorAll('#domInspector li.branch');
+    for ( var branch of branches ) {
+        branch.classList.toggle('show', state);
     }
 };
 
+var toggleHCompactView = function() {
+    inspector.classList.toggle('hCompact');
+};
+
 /******************************************************************************/
 
 var toggleHighlightMode = function() {
-    messaging.sendTo(
-        'loggerUI',
-        {
-            what: 'highlightMode',
-            invert: uDom.nodeFromSelector('#domInspector .permatoolbar .highlightMode').classList.toggle('invert')
-        },
-        inspectedTabId,
-        'domInspector'
-    );
+    messaging.sendTo(inspectorConnectionId, {
+        what: 'highlightMode',
+        invert: uDom.nodeFromSelector('#domInspector .permatoolbar .highlightMode').classList.toggle('invert')
+    });
 };
 
 /******************************************************************************/
 
 var revert = function() {
     uDom('#domTree .off').removeClass('off');
-    messaging.sendTo(
-        'loggerUI',
-        { what: 'resetToggledNodes' },
-        inspectedTabId,
-        'domInspector'
-    );
+    messaging.sendTo(inspectorConnectionId, { what: 'resetToggledNodes' });
     inspector.querySelector('.permatoolbar .revert').classList.add('disabled');
     inspector.querySelector('.permatoolbar .commit').classList.add('disabled');
 };
@@ -739,8 +632,10 @@ var revert = function() {
 var toggleOn = function() {
     window.addEventListener('beforeunload', toggleOff);
     tabSelector.addEventListener('change', onTabIdChanged);
-    domTree.addEventListener('click', onClick, true);
+    domTree.addEventListener('click', onClicked, true);
     domTree.addEventListener('mouseover', onMouseOver, true);
+    uDom.nodeFromSelector('#domInspector .vCompactToggler').addEventListener('click', toggleVCompactView);
+    uDom.nodeFromSelector('#domInspector .hCompactToggler').addEventListener('click', toggleHCompactView);
     uDom.nodeFromSelector('#domInspector .permatoolbar .highlightMode').addEventListener('click', toggleHighlightMode);
     uDom.nodeFromSelector('#domInspector .permatoolbar .revert').addEventListener('click', revert);
     uDom.nodeFromSelector('#domInspector .permatoolbar .commit').addEventListener('click', startDialog);
@@ -753,8 +648,10 @@ var toggleOff = function() {
     shutdownInspector();
     window.removeEventListener('beforeunload', toggleOff);
     tabSelector.removeEventListener('change', onTabIdChanged);
-    domTree.removeEventListener('click', onClick, true);
+    domTree.removeEventListener('click', onClicked, true);
     domTree.removeEventListener('mouseover', onMouseOver, true);
+    uDom.nodeFromSelector('#domInspector .vCompactToggler').removeEventListener('click', toggleVCompactView);
+    uDom.nodeFromSelector('#domInspector .hCompactToggler').removeEventListener('click', toggleHCompactView);
     uDom.nodeFromSelector('#domInspector .permatoolbar .highlightMode').removeEventListener('click', toggleHighlightMode);
     uDom.nodeFromSelector('#domInspector .permatoolbar .revert').removeEventListener('click', revert);
     uDom.nodeFromSelector('#domInspector .permatoolbar .commit').removeEventListener('click', startDialog);
diff --git a/src/js/logger-ui.js b/src/js/logger-ui.js
index dd00f92d956d0..218f44fb31bb3 100644
--- a/src/js/logger-ui.js
+++ b/src/js/logger-ui.js
@@ -412,12 +412,8 @@ var synchronizeTabIds = function(newTabIds) {
     var rowVoided = false;
     var trs;
     for ( var tabId in oldTabIds ) {
-        if ( oldTabIds.hasOwnProperty(tabId) === false ) {
-            continue;
-        }
-        if ( newTabIds.hasOwnProperty(tabId) ) {
-            continue;
-        }
+        if ( oldTabIds.hasOwnProperty(tabId) === false ) { continue; }
+        if ( newTabIds.hasOwnProperty(tabId) ) { continue; }
         // Mark or remove voided rows
         trs = uDom('.tab_' + tabId);
         if ( autoDeleteVoidRows ) {
@@ -440,9 +436,7 @@ var synchronizeTabIds = function(newTabIds) {
     var option;
     for ( var i = 0, j = 2; i < tabIds.length; i++ ) {
         tabId = tabIds[i];
-        if ( tabId === noTabId ) {
-            continue;
-        }
+        if ( tabId === noTabId ) { continue; }
         option = select.options[j];
         if ( !option ) {
             option = document.createElement('option');
@@ -1515,8 +1509,8 @@ var cleanBuffer = function() {
 
 /******************************************************************************/
 
-var toggleCompactView = function() {
-    uDom.nodeFromId('netInspector').classList.toggle('compactView');
+var toggleVCompactView = function() {
+    uDom.nodeFromId('netInspector').classList.toggle('vCompact');
 };
 
 /******************************************************************************/
@@ -1646,7 +1640,7 @@ uDom('#pageSelector').on('change', pageSelectorChanged);
 uDom('#refresh').on('click', reloadTab);
 uDom('#showdom').on('click', toggleInspectors);
 
-uDom('#compactViewToggler').on('click', toggleCompactView);
+uDom('#netInspector .vCompactToggler').on('click', toggleVCompactView);
 uDom('#clean').on('click', cleanBuffer);
 uDom('#clear').on('click', clearBuffer);
 uDom('#maxEntries').on('change', onMaxEntriesChanged);
diff --git a/src/js/scriptlets/dom-inspector.js b/src/js/scriptlets/dom-inspector.js
index e306945e4e69c..826018e8a79c4 100644
--- a/src/js/scriptlets/dom-inspector.js
+++ b/src/js/scriptlets/dom-inspector.js
@@ -137,6 +137,8 @@ var cssEscape = (function(/*root*/) {
 /******************************************************************************/
 /******************************************************************************/
 
+var loggerConnectionId;
+
 // Highlighter-related
 var svgRoot = null;
 var pickerRoot = null;
@@ -153,29 +155,16 @@ var reHasCSSCombinators = /[ >+~]/;
 
 /******************************************************************************/
 
-// Some kind of fingerprint for the DOM, without incurring too much overhead.
-
-var domFingerprint = function() {
-    return sessionId;
-};
-
-/******************************************************************************/
-
 var domLayout = (function() {
-    var skipTagNames = {
-        'br': true,
-        'link': true,
-        'meta': true,
-        'script': true,
-        'style': true
-    };
-
-    var resourceAttrNames = {
-        'a': 'href',
-        'iframe': 'src',
-        'img': 'src',
-        'object': 'data'
-    };
+    var skipTagNames = new Set([
+        'br', 'head', 'link', 'meta', 'script', 'style', 'title'
+    ]);
+    var resourceAttrNames = new Map([
+        [ 'a', 'href' ],
+        [ 'iframe', 'src' ],
+        [ 'img', 'src' ],
+        [ 'object', 'data' ]
+    ]);
 
     var idGenerator = 0;
 
@@ -206,11 +195,15 @@ var domLayout = (function() {
             }
         }
         // Tag-specific attributes
-        if ( resourceAttrNames.hasOwnProperty(tag) ) {
-            attr = resourceAttrNames[tag];
+        attr = resourceAttrNames.get(tag);
+        if ( attr !== undefined ) {
             str = node.getAttribute(attr) || '';
             str = str.trim();
-            pos = str.indexOf('#');
+            if ( str.startsWith('data:') ) {
+                pos = 5;
+            } else {
+                pos = str.search(/[#?]/);
+            }
             if ( pos !== -1 ) {
                 str = str.slice(0, pos);
                 sw = '^';
@@ -242,13 +235,9 @@ var domLayout = (function() {
 
     var domNodeFactory = function(level, node) {
         var localName = node.localName;
-        if ( skipTagNames.hasOwnProperty(localName) ) {
-            return null;
-        }
+        if ( skipTagNames.has(localName) ) { return null; }
         // skip uBlock's own nodes
-        if ( node.classList.contains(sessionId) ) {
-            return null;
-        }
+        if ( node.classList.contains(sessionId) ) { return null; }
         if ( level === 0 && localName === 'body' ) {
             return new DomRoot();
         }
@@ -260,7 +249,7 @@ var domLayout = (function() {
     var getLayoutData = function() {
         var layout = [];
         var stack = [];
-        var node = document.body;
+        var node = document.documentElement;
         var domNode;
         var lvl = 0;
 
@@ -324,37 +313,31 @@ var domLayout = (function() {
         return layout;
     };
 
-    // Track and report mutations to the DOM
+    // Track and report mutations of the DOM
 
     var mutationObserver = null;
-    var mutationTimer = null;
+    var mutationTimer;
     var addedNodelists = [];
     var removedNodelist = [];
-    var journalEntries = [];
-    var journalNodes = Object.create(null);
 
     var previousElementSiblingId = function(node) {
         var sibling = node;
         for (;;) {
             sibling = sibling.previousElementSibling;
-            if ( sibling === null ) {
-                return null;
-            }
-            if ( skipTagNames.hasOwnProperty(sibling.localName) ) {
-                continue;
-            }
+            if ( sibling === null ) { return null; }
+            if ( skipTagNames.has(sibling.localName) ) { continue; }
             return nodeToIdMap.get(sibling);
         }
     };
 
-    var journalFromBranch = function(root, added) {
+    var journalFromBranch = function(root, newNodes, newNodeToIdMap) {
         var domNode;
         var node = root.firstElementChild;
         while ( node !== null ) {
             domNode = domNodeFactory(undefined, node);
             if ( domNode !== null ) {
-                journalNodes[domNode.nid] = domNode;
-                added.push(node);
+                newNodeToIdMap.set(domNode.nid, domNode);
+                newNodes.push(node);
             }
             // down
             if ( node.firstElementChild !== null ) {
@@ -368,9 +351,7 @@ var domLayout = (function() {
             }
             // up then right
             for (;;) {
-                if ( node.parentElement === root ) {
-                    return;
-                }
+                if ( node.parentElement === root ) { return; }
                 node = node.parentElement;
                 if ( node.nextElementSibling !== null ) {
                     node = node.nextElementSibling;
@@ -381,51 +362,33 @@ var domLayout = (function() {
     };
 
     var journalFromMutations = function() {
-        mutationTimer = null;
-        if ( mutationObserver === null ) {
-            addedNodelists = [];
-            removedNodelist = [];
-            return;
-        }
-
-        var i, m, nodelist, j, n, node, domNode, nid;
+        var nodelist, node, domNode, nid;
 
         // This is used to temporarily hold all added nodes, before resolving
         // their node id and relative position.
-        var added = [];
-
-        for ( i = 0, m = addedNodelists.length; i < m; i++ ) {
-            nodelist = addedNodelists[i];
-            for ( j = 0, n = nodelist.length; j < n; j++ ) {
-                node = nodelist[j];
-                if ( node.nodeType !== 1 ) {
-                    continue;
-                }
-                // I don't think this can ever happen
-                if ( node.parentElement === null ) {
-                    continue;
-                }
+        var newNodes = [];
+        var journalEntries = [];
+        var newNodeToIdMap = new Map();
+
+        for ( nodelist of addedNodelists ) {
+            for ( node of nodelist ) {
+                if ( node.nodeType !== 1 ) { continue; }
+                if ( node.parentElement === null ) { continue; }
                 cosmeticFilterMapper.incremental(node);
                 domNode = domNodeFactory(undefined, node);
                 if ( domNode !== null ) {
-                    journalNodes[domNode.nid] = domNode;
-                    added.push(node);
+                    newNodeToIdMap.set(domNode.nid, domNode);
+                    newNodes.push(node);
                 }
-                journalFromBranch(node, added);
+                journalFromBranch(node, newNodes, newNodeToIdMap);
             }
         }
         addedNodelists = [];
-        for ( i = 0, m = removedNodelist.length; i < m; i++ ) {
-            nodelist = removedNodelist[i];
-            for ( j = 0, n = nodelist.length; j < n; j++ ) {
-                node = nodelist[j];
-                if ( node.nodeType !== 1 ) {
-                    continue;
-                }
+        for ( nodelist of removedNodelist ) {
+            for ( node of nodelist ) {
+                if ( node.nodeType !== 1 ) { continue; }
                 nid = nodeToIdMap.get(node);
-                if ( nid === undefined ) {
-                    continue;
-                }
+                if ( nid === undefined ) { continue; }
                 journalEntries.push({
                     what: -1,
                     nid: nid
@@ -433,8 +396,7 @@ var domLayout = (function() {
             }
         }
         removedNodelist = [];
-        for ( i = 0, n = added.length; i < n; i++ ) {
-            node = added[i];
+        for ( node of newNodes ) {
             journalEntries.push({
                 what: 1,
                 nid: nodeToIdMap.get(node),
@@ -442,12 +404,20 @@ var domLayout = (function() {
                 l: previousElementSiblingId(node)
             });
         }
+
+        if ( journalEntries.length === 0 ) { return; }
+
+        vAPI.messaging.sendTo(loggerConnectionId, {
+            what: 'domLayoutIncremental',
+            url: window.location.href,
+            hostname: window.location.hostname,
+            journal: journalEntries,
+            nodes: Array.from(newNodeToIdMap)
+        });
     };
 
     var onMutationObserved = function(mutationRecords) {
-        var record;
-        for ( var i = 0, n = mutationRecords.length; i < n; i++ ) {
-            record = mutationRecords[i];
+        for ( var record of mutationRecords ) {
             if ( record.addedNodes.length !== 0 ) {
                 addedNodelists.push(record.addedNodes);
             }
@@ -455,55 +425,27 @@ var domLayout = (function() {
                 removedNodelist.push(record.removedNodes);
             }
         }
-        if ( mutationTimer === null ) {
+        if ( mutationTimer === undefined ) {
             mutationTimer = vAPI.setTimeout(journalFromMutations, 1000);
         }
     };
 
     // API
 
-    var getLayout = function(fingerprint) {
-        if ( fingerprint !== domFingerprint() ) {
-            reset();
-        }
+    var getLayout = function() {
+        cosmeticFilterMapper.reset();
+        mutationObserver = new MutationObserver(onMutationObserved);
+        mutationObserver.observe(document.body, {
+            childList: true,
+            subtree: true
+        });
 
-        var response = {
-            what: 'domLayout',
-            fingerprint: domFingerprint(),
+        return {
+            what: 'domLayoutFull',
             url: window.location.href,
-            hostname: window.location.hostname
+            hostname: window.location.hostname,
+            layout: patchLayoutData(getLayoutData())
         };
-
-        if ( document.readyState !== 'complete' ) {
-            response.status = 'busy';
-            return response;
-        }
-
-        // No mutation observer means we need to send full layout
-        if ( mutationObserver === null ) {
-            cosmeticFilterMapper.reset();
-            mutationObserver = new MutationObserver(onMutationObserved);
-            mutationObserver.observe(document.body, {
-                childList: true,
-                subtree: true
-            });
-            response.status = 'full';
-            response.layout = patchLayoutData(getLayoutData());
-            return response;
-        }
-
-        // Incremental layout
-        if ( journalEntries.length !== 0 ) {
-            response.status = 'incremental';
-            response.journal = journalEntries;
-            response.nodes = journalNodes;
-            journalEntries = [];
-            journalNodes = Object.create(null);
-            return response;
-        }
-
-        response.status = 'nochange';
-        return response;
     };
 
     var reset = function() {
@@ -511,9 +453,9 @@ var domLayout = (function() {
     };
 
     var shutdown = function() {
-        if ( mutationTimer !== null ) {
+        if ( mutationTimer !== undefined ) {
             clearTimeout(mutationTimer);
-            mutationTimer = null;
+            mutationTimer = undefined;
         }
         if ( mutationObserver !== null ) {
             mutationObserver.disconnect();
@@ -521,8 +463,6 @@ var domLayout = (function() {
         }
         addedNodelists = [];
         removedNodelist = [];
-        journalEntries = [];
-        journalNodes = Object.create(null);
         nodeToIdMap = new WeakMap();
     };
 
@@ -550,136 +490,6 @@ try {
 
 /******************************************************************************/
 
-var cosmeticFilterFromEntries = function(entries) {
-    var out = [];
-    var entry, i = entries.length;
-    while ( i-- ) {
-        entry = entries[i];
-        out.push(cosmeticFilterFromTarget(entry.nid, entry.selector));
-    }
-    return out;
-};
-
-/******************************************************************************/
-
-// Extract the best possible cosmetic filter, i.e. as specific as possible.
-
-var cosmeticFilterFromNode = function(elem) {
-    var tagName = elem.localName;
-    var prefix = '';
-    var suffix = [];
-    var v, i;
-
-    // Id
-    v = typeof elem.id === 'string' && cssEscape(elem.id);
-    if ( v ) {
-        suffix.push('#', v);
-    }
-
-    // Class(es)
-    if ( suffix.length === 0 ) {
-        v = elem.classList;
-        if ( v ) {
-            i = v.length || 0;
-            while ( i-- ) {
-                suffix.push('.' + cssEscape(v.item(i)));
-            }
-        }
-    }
-
-    // Tag name
-    if ( suffix.length === 0 ) {
-        prefix = tagName;
-    }
-
-    // Attributes (depends on tag name)
-    var attributes = [], attr;
-    switch ( tagName ) {
-    case 'a':
-        v = elem.getAttribute('href');
-        if ( v ) {
-            v = v.replace(/\?.*$/, '');
-            if ( v.length ) {
-                attributes.push({ k: 'href', v: v });
-            }
-        }
-        break;
-    case 'img':
-        v = elem.getAttribute('alt');
-        if ( v && v.length !== 0 ) {
-            attributes.push({ k: 'alt', v: v });
-        }
-        break;
-    default:
-        break;
-    }
-    while ( (attr = attributes.pop()) ) {
-        if ( attr.v.length === 0 ) {
-            continue;
-        }
-        suffix.push('[', attr.k, '="', cssEscape(attr.v, true), '"]');
-    }
-
-    var selector = prefix + suffix.join('');
-
-    // https://github.com/chrisaljoudi/uBlock/issues/637
-    // If the selector is still ambiguous at this point, further narrow using
-    // `nth-of-type`. It is preferable to use `nth-of-type` as opposed to
-    // `nth-child`, as `nth-of-type` is less volatile.
-    var parent = elem.parentElement;
-    if ( elementsFromSelector(cssScope + selector, parent).length > 1 ) {
-        i = 1;
-        while ( elem.previousElementSibling !== null ) {
-            elem = elem.previousElementSibling;
-            if ( elem.localName !== tagName ) {
-                continue;
-            }
-            i++;
-        }
-        selector += ':nth-of-type(' + i + ')';
-    }
-
-    return selector;
-};
-
-/******************************************************************************/
-
-var cosmeticFilterFromTarget = function(nid, coarseSelector) {
-    var elems = elementsFromSelector(coarseSelector);
-    var target = null;
-    var i = elems.length;
-    while ( i-- ) {
-        if ( nodeToIdMap.get(elems[i]) === nid ) {
-            target = elems[i];
-            break;
-        }
-    }
-    if ( target === null ) {
-        return coarseSelector;
-    }
-    // Find the most concise selector from the target node
-    var segments = [], segment;
-    var node = target;
-    while ( node !== document.body ) {
-        segment = cosmeticFilterFromNode(node);
-        segments.unshift(segment);
-        if ( segment.charAt(0) === '#' ) {
-            break;
-        }
-        node = node.parentElement;
-    }
-    var fineSelector = segments.join(' > ');
-    if ( fineSelector.charAt(0) === '#' ) {
-        return fineSelector;
-    }
-    if ( fineSelector.charAt(0) === '.' && elementsFromSelector(fineSelector).length === 1 ) {
-        return fineSelector;
-    }
-    return 'body > ' + fineSelector;
-};
-
-/******************************************************************************/
-
 var cosmeticFilterMapper = (function() {
     // https://github.com/gorhill/uBlock/issues/546
     var matchesFnName;
@@ -735,7 +545,6 @@ var cosmeticFilterMapper = (function() {
     };
 
     var incremental = function(rootNode) {
-        vAPI.domFilterer.toggle(false);
         nodesFromStyleTag(rootNode);
     };
 
@@ -821,13 +630,10 @@ var getSvgRootChildren = function() {
     }
 };
 
-var highlightElements = function(scrollTo) {
-    var wv = pickerRoot.contentWindow.innerWidth;
-    var hv = pickerRoot.contentWindow.innerHeight;
+var highlightElements = function() {
     var islands;
     var elem, rect, poly;
     var xl, xr, yt, yb, w, h, ws;
-    var xlu = Number.MAX_VALUE, xru = 0, ytu = Number.MAX_VALUE, ybu = 0;
     var svgRootChildren = getSvgRootChildren();
 
     islands = [];
@@ -914,43 +720,23 @@ var highlightElements = function(scrollTo) {
         islands.push(poly);
     }
     svgRootChildren[3].setAttribute('d', islands.join('') || 'M0 0');
-
-    if ( !scrollTo ) {
-        return;
-    }
-
-    // Highlighted area completely within viewport
-    if ( xlu >= 0 && xru <= wv && ytu >= 0 && ybu <= hv ) {
-        return;
-    }
-
-    var dx = 0, dy = 0;
-
-    if ( xru > wv ) {
-        dx = xru - wv;
-        xlu -= dx;
-    }
-    if ( xlu <  0 ) {
-        dx += xlu;
-    }
-    if ( ybu > hv ) {
-        dy = ybu - hv;
-        ytu -= dy;
-    }
-    if ( ytu <  0 ) {
-        dy += ytu;
-    }
-
-    if ( dx !== 0 || dy !== 0 ) {
-        window.scrollBy(dx, dy);
-    }
 };
 
 /******************************************************************************/
 
-var onScrolled = function() {
-    highlightElements();
-};
+var onScrolled = (function() {
+    var buffered = false;
+    var timerHandler = function() {
+        buffered = false;
+        highlightElements();
+    };
+    return function() {
+        if ( buffered === false ) {
+            window.requestAnimationFrame(timerHandler);
+            buffered = true;
+        }
+    };
+})();
 
 /******************************************************************************/
 
@@ -979,17 +765,6 @@ var nodesFromFilter = function(selector) {
 
 /******************************************************************************/
 
-var shutdown = function() {
-    cosmeticFilterMapper.shutdown();
-    domLayout.shutdown();
-    vAPI.messaging.removeAllChannelListeners('domInspector');
-    window.removeEventListener('scroll', onScrolled, true);
-    document.documentElement.removeChild(pickerRoot);
-    pickerRoot = svgRoot = null;
-};
-
-/******************************************************************************/
-
 var toggleExceptions = function(nodes, targetState) {
     for ( var node of nodes ) {
         if ( targetState ) {
@@ -1010,25 +785,57 @@ var toggleFilter = function(nodes, targetState) {
     }
 };
 
+var resetToggledNodes = function() {
+    rwGreenNodes.clear();
+    rwRedNodes.clear();
+};
+
 // https://www.youtube.com/watch?v=L5jRewnxSBY
 
+/******************************************************************************/
+
+var start = function() {
+    var onReady = function(ev) {
+        if ( ev ) {
+            document.removeEventListener(ev.type, onReady);
+        }
+        vAPI.messaging.sendTo(loggerConnectionId, domLayout.get());
+        vAPI.domFilterer.toggle(false);
+        highlightElements();
+    };
+    if ( document.readyState === 'loading' ) {
+        document.addEventListener('DOMContentLoaded', onReady);
+    } else {
+        onReady();
+    }
+};
+
+/******************************************************************************/
+
+var shutdown = function() {
+    cosmeticFilterMapper.shutdown();
+    domLayout.shutdown();
+    vAPI.messaging.disconnectFrom(loggerConnectionId);
+    window.removeEventListener('scroll', onScrolled, true);
+    document.documentElement.removeChild(pickerRoot);
+    pickerRoot = svgRoot = null;
+};
+
 /******************************************************************************/
 /******************************************************************************/
 
 var onMessage = function(request) {
-    var response;
+    var response,
+        nodes;
 
     switch ( request.what ) {
     case 'commitFilters':
         highlightElements();
         break;
 
-    case 'cookFilters':
-        response = cosmeticFilterFromEntries(request.entries);
-        break;
-
     case 'domLayout':
-        response = domLayout.get(request.fingerprint);
+        response = domLayout.get();
+        highlightElements();
         break;
 
     case 'highlightMode':
@@ -1037,13 +844,18 @@ var onMessage = function(request) {
 
     case 'highlightOne':
         blueNodes = selectNodes(request.selector, request.nid);
-        highlightElements(request.scrollTo);
+        highlightElements();
+        break;
+
+    case 'resetToggledNodes':
+        resetToggledNodes();
+        highlightElements();
         break;
 
     case 'showCommitted':
         blueNodes = [];
         // TODO: show only the new filters and exceptions.
-        highlightElements(true);
+        highlightElements();
         break;
 
     case 'showInteractive':
@@ -1052,23 +864,17 @@ var onMessage = function(request) {
         break;
 
     case 'toggleFilter':
-        toggleExceptions(
-            nodesFromFilter(request.filter),
-            request.target
-        );
-        highlightElements(true);
+        nodes = selectNodes(request.selector, request.nid);
+        if ( nodes.length !== 0 ) { nodes[0].scrollIntoView(); }
+        toggleExceptions(nodesFromFilter(request.filter), request.target);
+        highlightElements();
         break;
 
     case 'toggleNodes':
-        toggleFilter(
-            selectNodes(request.selector, request.nid),
-            request.target
-        );
-        highlightElements(true);
-        break;
-
-    case 'shutdown':
-        shutdown();
+        nodes = selectNodes(request.selector, request.nid);
+        if ( nodes.length !== 0 ) { nodes[0].scrollIntoView(); }
+        toggleFilter(nodes, request.target);
+        highlightElements();
         break;
 
     default:
@@ -1078,42 +884,35 @@ var onMessage = function(request) {
     return response;
 };
 
+var messagingHandler = function(msg) {
+    switch ( msg.what ) {
+    case 'connectionAccepted':
+        loggerConnectionId = msg.id;
+        start();
+        break;
+    case 'connectionBroken':
+        shutdown();
+        break;
+    case 'connectionMessage':
+        onMessage(msg.payload);
+        break;
+    }
+};
+
 /******************************************************************************/
 
 // Install DOM inspector widget
 
-pickerRoot = document.createElement('iframe');
-pickerRoot.classList.add(sessionId);
-pickerRoot.classList.add('dom-inspector');
-pickerRoot.style.cssText = [
-    'background: transparent',
-    'border: 0',
-    'border-radius: 0',
-    'box-shadow: none',
-    'display: block',
-    'height: 100%',
-    'left: 0',
-    'margin: 0',
-    'opacity: 1',
-    'position: fixed',
-    'outline: 0',
-    'padding: 0',
-    'top: 0',
-    'visibility: visible',
-    'width: 100%',
-    'z-index: 2147483647',
-    ''
-].join(' !important;\n');
-
-pickerRoot.onload = function() {
-    pickerRoot.onload = null;
+var bootstrap = function(ev) {
+    if ( ev ) {
+        pickerRoot.removeEventListener(ev.type, bootstrap);
+    }
     var pickerDoc = this.contentDocument;
 
     var style = pickerDoc.createElement('style');
     style.textContent = [
         'body {',
             'background-color: transparent;',
-            'cursor: not-allowed;',
         '}',
         'svg {',
             'height: 100%;',
@@ -1155,9 +954,34 @@ pickerRoot.onload = function() {
     cosmeticFilterMapper.reset();
     highlightElements();
 
-    vAPI.messaging.addChannelListener('domInspector', onMessage);
+    vAPI.messaging.connectTo('domInspector', 'loggerUI', messagingHandler);
 };
 
+pickerRoot = document.createElement('iframe');
+pickerRoot.classList.add(sessionId);
+pickerRoot.classList.add('dom-inspector');
+pickerRoot.style.cssText = [
+    'background: transparent',
+    'border: 0',
+    'border-radius: 0',
+    'box-shadow: none',
+    'display: block',
+    'height: 100%',
+    'left: 0',
+    'margin: 0',
+    'opacity: 1',
+    'position: fixed',
+    'outline: 0',
+    'padding: 0',
+    'pointer-events:none;',
+    'top: 0',
+    'visibility: visible',
+    'width: 100%',
+    'z-index: 2147483647',
+    ''
+].join(' !important;\n');
+
+pickerRoot.addEventListener('load', bootstrap);
 document.documentElement.appendChild(pickerRoot);
 
 /******************************************************************************/
diff --git a/src/js/ublock.js b/src/js/ublock.js
index d22a36de7554f..9896a43c64af0 100644
--- a/src/js/ublock.js
+++ b/src/js/ublock.js
@@ -579,14 +579,14 @@ var reInvalidHostname = /[^a-z0-9.\-\[\]:]/,
             pendingEntries.set(key, new Entry(tabId, scriptlet, callback));
         }
         vAPI.tabs.injectScript(tabId, {
-            file: 'js/scriptlets/' + scriptlet + '.js'
+            file: '/js/scriptlets/' + scriptlet + '.js'
         });
     };
 
     // TODO: think about a callback mechanism.
     var injectDeep = function(tabId, scriptlet) {
         vAPI.tabs.injectScript(tabId, {
-            file: 'js/scriptlets/' + scriptlet + '.js',
+            file: '/js/scriptlets/' + scriptlet + '.js',
             allFrames: true
         });
     };
diff --git a/src/logger-ui.html b/src/logger-ui.html
index 34740fc696b66..9539f44a90e79 100644
--- a/src/logger-ui.html
+++ b/src/logger-ui.html
@@ -16,15 +16,17 @@
             <option value="" data-i18n="logAll">
             <option value="tab_bts" data-i18n="logBehindTheScene">
         </select>
-        <span id="refresh" class="button disabled fa needtab">&#xf021;</span>
+        <span id="refresh" class="button fa disabled needtab">&#xf021;</span>
         <span id="showdom" class="button fa">&#xf121;</span>
     </div>
 </div>
 
 <div id="inspectors">
-    <div id="domInspector" class="inspector">
+    <div id="domInspector" class="inspector vCompact hCompact">
         <div class="permatoolbar">
             <div>
+                <span class="button fa vCompactToggler"></span>
+                <span class="button fa hCompactToggler"></span>
                 <span class="button fa highlightMode" style="display: none">&#xf042;</span>
                 <span class="button fa revert disabled">&#xf12d;</span>
                 <span class="button fa commit disabled">&#xf0c7;</span>
@@ -35,10 +37,10 @@
         </div>
     </div>
 
-    <div id="netInspector" class="inspector compactView f">
+    <div id="netInspector" class="inspector vCompact f">
         <div class="permatoolbar">
             <div>
-                <span id="compactViewToggler" class="button fa"></span>
+                <span class="button fa vCompactToggler"></span>
                 <span id="clean" class="button fa disabled">&#xf00d;</span>
                 <span id="clear" class="button fa disabled">&#xf12d;</span>
                 <span id="filterButton" class="button fa">&#xf0b0;</span><input id="filterInput" type="text" placeholder="logFilterPrompt">