[Pale-Moon] Issue #1972 - Make sure all tab activity is halted before removal.

application/palemoon/base/content/tabbrowser.xml

@@ -2125,6 +2125,12 @@
             }
 
             // We're going to remove the tab and the browser now.
+            
+            // Interrupt all tab activity to aid in cleaning up detached window objects.
+            // Using the "superstop" should halt all animations, fetches, network activity
+            // etc. to come to a clean state for removal and unlinking (if enabled).
+            BrowserStop();
+            
             // Clean up mTabFilters and mTabListeners now rather than in
             // _beginRemoveTab, so that their size is always in sync with the
             // number of tabs and browsers (the xbl destructor depends on this).