Ensure PersistedElements are refreshed when AuxPanel scrolls

If the screen is not tall enough, AuxPanel starts scrolling its content.
If it contains PersistedElements, they need to be notified about
scrolling as they only listen on resize events to move their element.

Signed-off-by: Pauli Virtanen <pav@iki.fi>

src/components/views/rooms/AuxPanel.js

@@ -141,6 +141,15 @@ export default createReactClass({
         return counters;
     },
 
+    _onScroll: function(rect) {
+        if (this.props.onResize) {
+            this.props.onResize();
+        }
+
+        /* Force refresh of PersistedElements which may be partially hidden */
+        window.dispatchEvent(new Event('resize'));
+    },
+
     render: function() {
         const CallView = sdk.getComponent("voip.CallView");
         const TintableSvg = sdk.getComponent("elements.TintableSvg");
@@ -265,7 +274,7 @@ export default createReactClass({
         }
 
         return (
-            <AutoHideScrollbar className={classes} style={style} >
+            <AutoHideScrollbar className={classes} style={style} onScroll={this._onScroll}>
                 { stateViews }
                 { appsDrawer }
                 { fileDropTarget }