Bug 888867 - chat nub not sized correctly on a Mac retina screen, r=mixedpuppy.

browser/themes/shared/social/chat.inc.css

@@ -124,6 +124,10 @@ chatbar > chatbox > .chat-titlebar > .chat-swap-button:hover {
   }
 }
 
+.chatbar-button > .toolbarbutton-icon {
+  width: 16px;
+}
+
 .chatbar-button > menupopup > .menuitem-iconic > .menu-iconic-left > .menu-iconic-icon {
   width: auto;
   height: auto;