Expose -privatesendmultisession to GUI options

src/qt/forms/optionsdialog.ui

@@ -173,6 +173,16 @@
             </property>
            </widget>
           </item>
+          <item>
+           <widget class="QCheckBox" name="privateSendMultiSession">
+            <property name="toolTip">
+             <string>Whether to use experimental PrivateSend mode with multiple mixing sessions per block.&lt;br/&gt;Note: You must use this feature carefully.&lt;br/&gt;Make sure you always have recent wallet (auto)backup in a safe place!</string>
+            </property>
+            <property name="text">
+             <string>Enable PrivateSend &amp;multi-session</string>
+            </property>
+           </widget>
+          </item>
           <item>
            <widget class="QCheckBox" name="spendZeroConfChange">
             <property name="toolTip">

src/qt/optionsdialog.cpp

@@ -201,6 +201,7 @@ void OptionsDialog::setMapper()
     mapper->addMapping(ui->coinControlFeatures, OptionsModel::CoinControlFeatures);
     mapper->addMapping(ui->privateSendRounds, OptionsModel::PrivateSendRounds);
     mapper->addMapping(ui->anonymizeDash, OptionsModel::AnonymizeDashAmount);
+    mapper->addMapping(ui->privateSendMultiSession, OptionsModel::PrivateSendMultiSession);
 
     /* Network */
     mapper->addMapping(ui->mapPortUpnp, OptionsModel::MapPortUPnP);

src/qt/optionsmodel.cpp

@@ -131,6 +131,12 @@ void OptionsModel::Init(bool resetSettings)
     if (!SoftSetArg("-anonymizedashamount", settings.value("nAnonymizeDashAmount").toString().toStdString()))
         addOverriddenOption("-anonymizedashamount");
     nAnonymizeDashAmount = settings.value("nAnonymizeDashAmount").toInt();
+
+    if (!settings.contains("fPrivateSendMultiSession"))
+        settings.setValue("fPrivateSendMultiSession", fPrivateSendMultiSession);
+    if (!SoftSetBoolArg("-privatesendmultisession", settings.value("fPrivateSendMultiSession").toBool()))
+        addOverriddenOption("-privatesendmultisession");
+    fPrivateSendMultiSession = settings.value("fPrivateSendMultiSession").toBool();
 #endif
 
     // Network
@@ -251,6 +257,8 @@ QVariant OptionsModel::data(const QModelIndex & index, int role) const
             return settings.value("nAnonymizeDashAmount");
         case ShowMasternodesTab:
             return settings.value("fShowMasternodesTab");
+        case PrivateSendMultiSession:
+            return settings.value("fPrivateSendMultiSession");
 #endif
         case DisplayUnit:
             return nDisplayUnit;
@@ -400,6 +408,13 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
                 setRestartRequired(true);
             }
             break;
+        case PrivateSendMultiSession:
+            if (settings.value("fPrivateSendMultiSession") != value)
+            {
+                fPrivateSendMultiSession = value.toBool();
+                settings.setValue("fPrivateSendMultiSession", fPrivateSendMultiSession);
+            }
+            break;
 #endif
         case DisplayUnit:
             setDisplayUnit(value);

src/qt/optionsmodel.h

@@ -50,6 +50,7 @@ class OptionsModel : public QAbstractListModel
         PrivateSendRounds,      // int
         AnonymizeDashAmount,    // int
         ShowMasternodesTab,     // bool
+        PrivateSendMultiSession,// bool
         Listen,                 // bool
         OptionIDRowCount,
     };