browser_bug553455.js has a popup notification and want so close and re-open it by clicking the anchor icon, using EventUtils.synthesizeMouseAtCenter. The slide-in transition from bug 767133 caused this to fail even though it shouldn't affect the anchor at all. bug 767133 comment 14: This code should be clicking on the panel's anchor twice immediately after the panel opens (in the popupshown event). It looks like with these changes the anchor isn't seeing those clicks any more. I think the arrow panel is over the top of it at that point with this change. Waiting till the transform is done probably won't help much as the panel this test checks is short-lived and goes away when a very short download completes. bug 767133 comment 15: The transform affects the panel content, not the panel itself; the panel remains at the same position throughout the transition and the content is cut off at the top rather than overflowing the panel. So if synthesizeMouse thinks the anchor is blocked, that's a bug

Mass closing mochitest bugs that haven't had activity in the past 5 years. Please re-open or file a new bug with modern context if this is still relevant.