fix volume panel: auto-collapse expanded state when hover leaves

modules/Volume.qml

@@ -31,7 +31,21 @@ M.BarSection {
 
     property bool _expanded: false
     property bool _panelHovered: false
-    readonly property bool _showPanel: root._hovered || _panelHovered || _expanded
+    readonly property bool _anyHover: root._hovered || _panelHovered
+    readonly property bool _showPanel: _anyHover || _expanded
+
+    on_AnyHoverChanged: {
+        if (_anyHover)
+            _collapseTimer.stop();
+        else if (_expanded)
+            _collapseTimer.start();
+    }
+
+    Timer {
+        id: _collapseTimer
+        interval: 500
+        onTriggered: root._expanded = false
+    }
 
     M.BarIcon {
         icon: root._volumeIcon