[Bug 272510] Mac theme doesn't display focus for message grouping

mail/base/skin/mac/mailWindow1.css

@@ -214,25 +214,6 @@ treechildren::-moz-tree-cell-text(folderNameCol, noSelect-true) {
 
 /* ::::: thread decoration ::::: */
 
-treechildren::-moz-tree-row(dummy)  {
-  background-color:  #F0F0F0;
-  margin-bottom: 1px;
-  padding-left: 2px;
-}
-
-treechildren::-moz-tree-row(dummy, selected) {
-  background-color: -moz-Dialog;
-}
-
-treechildren::-moz-tree-row(dummy, selected, focus)  {
-  background-color: Highlight;
-}
-
-treechildren::-moz-tree-cell-text(dummy), treechildren::-moz-tree-cell(dummy) {
-  font-weight: normal !important;
-  color: #000 !important;
-}
-
 treechildren::-moz-tree-cell-text(read) {
   font-weight: normal;
 }
@@ -458,19 +439,15 @@ treechildren::-moz-tree-row(dummy)  {
 	margin-left: 1px;
 }
 
-treechildren::-moz-tree-row(dummy, selected) {
-	background-color: -moz-Dialog;
+treechildren::-moz-tree-row(dummy, focus, selected)  {
+	background-color: #3874d1;
+	border-color: #3874d1;
+	background-image: none !important;
+	margin: 0px;
+	padding-right: 1px;
+	padding-left: 1px;
 }
 
-treechildren::-moz-tree-row(dummy, selected, focus)  {
-	background-color: Highlight;
-}
-
-treechildren::-moz-tree-cell-text(dummy) {
-	font-weight: bold;
-}
-
-
 /* ::::: thread labels decoration ::::: */
 
 /* There are 10x7 color definitions (size of the color picker used)