It is *very important* to call super.onDetachedFromWindow()

Bug #10075732

Change-Id: I515005e35398317d98124964b6bb74f488a213f4
(cherry picked from commit 2361a4daf77ac1f076273d19bc6e171b3b74b22e)

src/com/android/launcher3/Workspace.java

@@ -1416,6 +1416,7 @@ public class Workspace extends SmoothPagedView
     }
 
     protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
         mWindowToken = null;
     }