diff --git a/mozilla/themes/classic/global/mac/outliner.css b/mozilla/themes/classic/global/mac/outliner.css
index 564a8f5e1e6..b5cfd7bf273 100644
--- a/mozilla/themes/classic/global/mac/outliner.css
+++ b/mozilla/themes/classic/global/mac/outliner.css
@@ -30,7 +30,7 @@
 /* ::::: outliner ::::: */
 
 outliner {
-  -moz-appearance: tree;
+  -moz-appearance: treeview;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
   -moz-border-right-colors: ThreeDHighlight ThreeDLightShadow;