--- PanelPopup.js	2010-01-23 11:32:24.000000000 +0100
+++ PanelPopup.fixed.js	2010-06-11 17:23:54.021476900 +0200
@@ -558,8 +558,12 @@
   if (!popup.origParent)
   {
     popup.origParent = popup.parentNode;
-  }  
-  parent.appendChild(popup);
+  } 
+  // Don't append the popup if it's already in the DOM 
+  if (parent != popup.parentNode) 
+  {
+      parent.appendChild(popup);
+  }
 
   if (!this._centered)
   {