put in Mike's change to Clear the selection when we take focus

this fixes the bug that the collection of ranges was monotonically increasing to infinity
as you clicked around in the document.

layout/base/src/nsRangeList.cpp

@@ -510,6 +510,7 @@ nsRangeList::TakeFocus(nsIFocusTracker *aTracker, nsIFrame *aFrame, PRInt32 aOff
       return NS_ERROR_NULL_POINTER;
   }
   //END HACK
+  Clear(); //change this later 
   nsIFrame *frame;
   nsIFrame *anchor;
   nsCOMPtr<nsIContent> content;