diff --git a/xpfe/global/resources/skin/tree.css b/xpfe/global/resources/skin/tree.css
index b0a4533ba2a..08576bf9049 100644
--- a/xpfe/global/resources/skin/tree.css
+++ b/xpfe/global/resources/skin/tree.css
@@ -111,12 +111,18 @@ treeitem[selected="true"][container="true"][open="true"] > treerow > treecell >
 
 
 /* tree header with sort direction indicators */
-treecell.sortDirectionIndicator[sortDirection="ascending"]  > .tree-header-sortdirection {
+.sortDirectionIndicator[sortDirection="ascending"]  > .tree-header-sortdirection {
   list-style-image: url("chrome://global/skin/sortAscending.gif");
   margin-right: 3px;
 }
 
-treecell.sortDirectionIndicator[sortDirection="descending"] > .tree-header-sortdirection {
+.sortDirectionIndicator[sortDirection="descending"] > .tree-header-sortdirection {
   list-style-image: url("chrome://global/skin/sortDescending.gif");
   margin-right: 3px;
 }
+
+treecol[sortDirection="true"],
+treecol[sortActive="true"]
+  {
+    background-color       : #DFDFDF;
+  }
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