Give up on showing a meaningful context menu in FF Mac

Just show the default menu

Author: marijnh

lib/codemirror.js

@@ -221,7 +221,7 @@ var CodeMirror = (function() {
       var start = posFromMouse(e);
       switch (e.button()) {
       case 3:
-        if (gecko) onContextMenu(e);
+        if (gecko && !mac) onContextMenu(e);
         return;
       case 2:
         if (start) setCursor(start.line, start.ch, true);