Since xulrunner 1.9 no longer has xinerama support, both Firefox and Thunderbird's menus only show on the primary monitor. I suspect any other xulrunner based apps will also be effected by this.
(In reply to comment #0) > Since xulrunner 1.9 no longer has xinerama support, both Firefox and > Thunderbird's menus only show on the primary monitor. I suspect any other > xulrunner based apps will also be effected by this. > Thunderbird has no bearing on this bug, there is no support to even build thunderbird against xulrunner.
I tested this with my dual-monitor xinerama system at work. All windows like the file-opening dialog, the download manager or the addon manager open on the same screen where firefox is located. One exception seems to be the "about" window, which always opens on my main screen. Unless you can provide more detailed information in which I request you to reopen this bug, I think it's INVALID.