diff --git a/src/viser/_gui_handles.py b/src/viser/_gui_handles.py
index 5138b48f..93aabf70 100644
--- a/src/viser/_gui_handles.py
+++ b/src/viser/_gui_handles.py
@@ -117,6 +117,9 @@ def __setattr__(self, name: str, value: Any) -> None:
         handle = cast(_GuiInputHandle, self)
         # Get the value of the T TypeVar.
         if name in self._prop_hints:
+            if getattr(handle._impl.props, name) == value:
+                # Do nothing. Assumes equality is defined for the prop value.
+                return
             setattr(handle._impl.props, name, value)
             handle._impl.gui_api._websock_interface.queue_message(
                 _messages.GuiUpdateMessage(handle._impl.id, {name: value})
@@ -489,7 +492,7 @@ def add_tab(self, label: str, icon: IconName | None = None) -> GuiTabHandle:
 
         self._tab_handles.append(out)
         self._tab_labels = self._tab_labels + (label,)
-        self._icons_html = self._icons_html + (
+        self._tab_icons_html = self._tab_icons_html + (
             None if icon is None else svg_from_icon(icon),
         )
         self._tab_container_ids = tuple(handle._id for handle in self._tab_handles)
@@ -551,9 +554,9 @@ def remove(self) -> None:
             self._parent._tab_labels[:found_index]
             + self._parent._tab_labels[found_index + 1 :]
         )
-        self._parent._icons_html = (
-            self._parent._icons_html[:found_index]
-            + self._parent._icons_html[found_index + 1 :]
+        self._parent._tab_icons_html = (
+            self._parent._tab_icons_html[:found_index]
+            + self._parent._tab_icons_html[found_index + 1 :]
         )
         self._parent._tab_handles = (
             self._parent._tab_handles[:found_index]
diff --git a/src/viser/_messages.py b/src/viser/_messages.py
index 0057c7f0..77748a44 100644
--- a/src/viser/_messages.py
+++ b/src/viser/_messages.py
@@ -14,7 +14,7 @@
 from . import infra, theme
 
 
-@dataclasses.dataclass
+@dataclasses.dataclass(frozen=True)
 class GuiSliderMark:
     value: float
     label: Optional[str]
diff --git a/src/viser/_scene_handles.py b/src/viser/_scene_handles.py
index 87c8b990..ec62e562 100644
--- a/src/viser/_scene_handles.py
+++ b/src/viser/_scene_handles.py
@@ -57,6 +57,10 @@ def __setattr__(self, name: str, value: Any) -> None:
             elif hint == onpt.NDArray[np.uint8] and "color" in name:
                 value = colors_to_uint8(value)
 
+            if getattr(handle._impl.props, name) == value:
+                # Do nothing. Assumes equality is defined for the prop value.
+                return
+
             setattr(handle._impl.props, name, value)
             handle._impl.api._websock_interface.queue_message(
                 _messages.SceneNodeUpdateMessage(handle.name, {name: value})
diff --git a/src/viser/client/src/ThreeAssets.tsx b/src/viser/client/src/ThreeAssets.tsx
index 5ce5717d..2d45dae1 100644
--- a/src/viser/client/src/ThreeAssets.tsx
+++ b/src/viser/client/src/ThreeAssets.tsx
@@ -601,24 +601,18 @@ export const ViserMesh = React.forwardRef<
     const state = viewer.skinnedMeshState.current[message.name];
     const bones = bonesRef.current;
     if (bones !== undefined) {
-      bones.forEach((bone, i) => {
-        if (!state.initialized) {
+      if (!state.initialized) {
+        bones.forEach((bone) => {
           parentNode.add(bone);
-        }
-        const wxyz = state.initialized
-          ? state.poses[i].wxyz
-          : message.props.bone_wxyzs[i];
-        const position = state.initialized
-          ? state.poses[i].position
-          : message.props.bone_positions[i];
-
+        });
+        state.initialized = true;
+      }
+      bones.forEach((bone, i) => {
+        const wxyz = state.poses[i].wxyz;
+        const position = state.poses[i].position;
         bone.quaternion.set(wxyz[1], wxyz[2], wxyz[3], wxyz[0]);
         bone.position.set(position[0], position[1], position[2]);
       });
-
-      if (!state.initialized) {
-        state.initialized = true;
-      }
     }
   });
 
diff --git a/src/viser/infra/_infra.py b/src/viser/infra/_infra.py
index e3f1e1b4..25d12956 100644
--- a/src/viser/infra/_infra.py
+++ b/src/viser/infra/_infra.py
@@ -442,13 +442,36 @@ async def viser_http_server(
 
             use_gzip = "gzip" in request_headers.get("Accept-Encoding", "")
 
-            mime_type = mimetypes.guess_type(relpath)[0]
+            # First, try some known MIME types. Using guess_type() can cause
+            # problems for Javascript on some Windows machines.
+            #
+            # Some references:
+            #     https://github.com/nerfstudio-project/viser/issues/256#issuecomment-2369684252
+            #     https://bugs.python.org/issue43975
+            #     https://github.com/golang/go/issues/32350#issuecomment-525111557
+            #
+            # We're assuming UTF-8, this is mostly reasonable but might want to revisit.
+            mime_type = {
+                ".css": "text/css; charset=utf-8",
+                ".gif": "image/gif",
+                ".htm": "text/html; charset=utf-8",
+                ".html": "text/html; charset=utf-8",
+                ".jpg": "image/jpeg",
+                ".js": "application/javascript",
+                ".wasm": "application/wasm",
+                ".pdf": "application/pdf",
+                ".png": "image/png",
+                ".svg": "image/svg+xml",
+                ".xml": "text/xml; charset=utf-8",
+            }.get(Path(path).suffix.lower(), None)
+            if mime_type is None:
+                mime_type = mimetypes.guess_type(relpath)[0]
             if mime_type is None:
                 mime_type = "application/octet-stream"
+
             response_headers = {
                 "Content-Type": mime_type,
             }
-
             if source_path not in file_cache:
                 file_cache[source_path] = source_path.read_bytes()
             if use_gzip: