fixed bug 105132 r=shliang sr=hewitt mac classic composer tabs cleanup

themes/classic/editor/mac/EditModeTabs.css

@@ -15,8 +15,6 @@
   margin-top: 0px;
   margin-bottom: 2px;
   border-top: none;
-  border-right: 1px solid threeddarkshadow;
-  -moz-border-radius: 0px 0px 5px 5px;
   -moz-user-focus: ignore;
 }