Comment 6 for bug 775229

I am having a similar issue. I can't reproduce it using Alex's steps; it seems to happen pretty much at random (though CTRL+ALT+ARROW seems to be a good way of starting and stopping the problem). For me, the menus do appear if I hold the mouse down for long enough, maybe half a second, but then disappear as soon as I move the mouse off the menu button (so it is impossible to click on a menu item). At the same time as this issue occurs, autoscroll starts behaving strangely - if I middle click, then move my mouse off the autoscroll icon, then move it back, the icon disappears and autoscrolling stops.

I am running Ubuntu 11.10 amd64 on a Dell Studio 1558, and have firefox 7.0.1 from the repositories, and the issue occurs in normal and safe mode. I am clicking using my touchpad's buttons (I have touchpad tapping disabled) and I have removed the firefox-globalmenu package because of #748850.