--- a/dom/events/test/window_bug659071.html
+++ b/dom/events/test/window_bug659071.html
@@ -43,19 +43,26 @@ function runTests()
        "failed to reset zoom");
     synthesizeWheel(video, 10, 10,
       { deltaMode: WheelEvent.DOM_DELTA_LINE, ctrlKey: true,
         deltaX: 0, deltaY: 1.0, lineOrPageDeltaX: 0, lineOrPageDeltaY: 1 });
     hitEventLoop(function () {
       isnot(SpecialPowers.getFullZoom(window), 1.0,
              "failed to zoom by ctrl+wheel");
 
-      synthesizeKey("0", { accelKey: true });
-      SpecialPowers.clearUserPref("mousewheel.with_control.action");
+      synthesizeWheel(video, 10, 10,
+        { deltaMode: WheelEvent.DOM_DELTA_LINE, ctrlKey: true,
+          deltaX: 0, deltaY: 1.0, lineOrPageDeltaX: 0, lineOrPageDeltaY: -1 });
+      hitEventLoop(function () {
+        is(SpecialPowers.getFullZoom(window), 1.0,
+           "failed to reset zoom");
 
-      hitEventLoop(window.opener.finish, 20);
+        SpecialPowers.clearUserPref("mousewheel.with_control.action");
+
+        hitEventLoop(window.opener.finish, 20);
+      }, 20);
     }, 20);
   }, 20);
 }
 
 </script>
 </body>
 </html>