Created attachment 670953 [details] screenshot I have a recent Aurora (either 2012-09-28 or 2012-10-08), and it was on about:addons when I started it up and left it running. Tested on Mac 10.7.5. Presumably a few moments later the doorhanger panel for Test Pilot will pop up - but because the bookmarks pane / feedback icon is not present, it latches itself to the top left corner and is not clickable. See screenshot. I workaround by quitting the browser. Thanks Matt for helping me look at this issue.