Context menu flashes and disappears Rated 4 out of 5 stars

After upgrading to Firefox 14.0.1, I have the same problem as skynet281978 reported. When I right click on a page or a tab button, the context menu flashes for a moment and disappears. This also happens with the pulldown menu on the tab bar, and the "tools for all addons" menu in the addon listing. The problem doesn't happen right away when I start Firefox, but after whatever triggers it, it will keep happening so I have to restart Firefox to use right click menu again. When it happens, right clicking shows an error in the console "TypeError: gContextMenu is null - chrome://gd12/content/gdic.js" (line 55, " if (gContextMenu.isTextSelected)").

This review is for a previous version of the add-on (5.10.1-signed).