Make folder tree take up the entire pane.

mailnews/ui/messenger/resources/folderPane.css

@@ -8,7 +8,8 @@ tree {
  background-color: white; 
  border: none; 
  border-spacing: 0px; 
- border-collapse: collapse; 
+ //border-collapse: collapse; 
+ width: 100%
 } 
 
 treeitem { 

mailnews/ui/messenger/resources/threadPane.css

@@ -1,6 +1,5 @@
 window {
  display: block;
- width: 100%;
  background-color: white;
 }