Bug 407529 - Show mode as symbol doesn't update tree display

r=silver@warwickcompsoc.co.uk (James Ross)
ChatZilla Only. NPOTFFB.

extensions/irc/xul/content/static.js

@@ -2691,7 +2691,10 @@ function setListMode(mode)
     else
         elem.removeAttribute("mode");
     if (elem && elem.view && elem.treeBoxObject)
+    {
         elem.treeBoxObject.clearStyleAndImageCaches();
+        elem.treeBoxObject.invalidate();
+    }
 }
 
 function updateUserList()