--- a/suite/themes/classic/mac/messenger/mailWindow1.css
+++ b/suite/themes/classic/mac/messenger/mailWindow1.css
@@ -80,26 +80,26 @@
   background-color: #CDCDCD;
   background-image: url("chrome://communicator/skin/toolbar-gradient34.png");
   background-repeat: repeat-x;
   border-bottom: 1px solid #9F9F9F;
 }
 
 /* Leopard-styled "zero-width" vertical splitter */
 
-#folderpane_splitter {
+#folderpane-splitter {
   border: solid #B3B3B3;
   border-width: 0 1px 0 0;
   min-width: 1px;
   background-image: none;
 }
 
 /* Make sure users find the splitter when it's collapsed... */
 
-#folderpane_splitter[state="collapsed"] {
+#folderpane-splitter[state="collapsed"] {
   min-width: 5px;
   background-color: #D6DDE5;
   cursor: e-resize;
 }
 
 /* Thick horisontal splitter */
 
 #threadpane-splitter {