MenuButton: Do not popup a sibling MenuButton if the current one has been closed.

[GB.FORM]
* BUG: MenuButton: Do not popup a sibling MenuButton if the current one has been closed.

comp/src/gb.form/.src/Button/MenuButton.class

@@ -139,9 +139,15 @@ Public Sub WatchTimer_Timer()
   Dim X As Integer
   Dim Y As Integer
   
+  If Not $hCurrentMenu Or If $hCurrentMenu.Closed Then
+    Last.Stop
+    Return
+  Endif
+  
   X = Mouse.ScreenX - Me.Parent.ScreenX
   Y = Mouse.ScreenY - Me.Parent.ScreenY
   
+  
   'Debug X;; Y
   
   If X < 0 Or If Y < 0 Or If X >= Me.Parent.W Or If Y >= Me.Parent.H Then Return