Fix focus problems for submenues in context menues

src/gui/Base/HMenu.qml

@@ -8,6 +8,7 @@ import CppUtils 0.1
 Menu {
     id: menu
 
+    property bool isSubMenu: false
     property var previouslyFocused: null
 
     // MenuItems that open popups (or other elements taking focus when opened)
@@ -57,6 +58,7 @@ Menu {
     }
 
     onAboutToShow: {
+        if (isSubMenu) return
         previouslyFocused = window.activeFocusItem
         focusOnClosed     = Qt.binding(() => previouslyFocused)
     }

src/gui/MainPane/RoomDelegate.qml

@@ -149,6 +149,7 @@ HTile {
 
         HMenu {
             title: qsTr("Notifications")
+            isSubMenu: true
 
             HMenuItem {
                 text: qsTr("Use default account settings")