Bug 746519 - ShiftTab from editable document fails on Linux and Mac, disable it

accessible/tests/mochitest/events/test_focus_general.html

@@ -109,8 +109,8 @@
       if (SEAMONKEY) {
         todo(false, "shift tab from editable document fails on (Windows) SeaMonkey! (Bug 718235)");
       } else {
-      if (LINUX)
-        todo(false, "shift tab from editable document fails on linux!");
+      if (LINUX || MAC)
+        todo(false, "shift tab from editable document fails on linux and Mac, bug 746519!");
       else
         gQueue.push(new synthShiftTab("link", new focusChecker("link")));
       } // ! SEAMONKEY