screenShield: Ensure we destroy background container widgets

We may accidentally leak a widget when monitors change while
locked otherwise. This is especially bad because we put a
box-shadow on this widget.

https://bugzilla.gnome.org/show_bug.cgi?id=697300

diff --git a/js/ui/screenShield.js b/js/ui/screenShield.js
index f8bf3ccb76251d6022a52ef88e74fba9e99d7d3e..d7e020b3191e9017f698c61d6e313517b667ffa9 100644 (file)
--- a/js/ui/screenShield.js
+++ b/js/ui/screenShield.js
@@ -562,6 +562,7 @@ const ScreenShield = new Lang.Class({
             this._bgManagers[i].destroy();
 
         this._bgManagers = [];
+        this._backgroundGroup.destroy_all_children();
 
         for (let i = 0; i < Main.layoutManager.monitors.length; i++)
             this._createBackground(i);