Mozilla/5.0 (X11; Linux x86_64; rv:6.0a1) Gecko/20110418 Firefox/6.0a1 SeaMonkey/2.2a1pre ID:20110418003002 This bug did not happen in yesterday's nightly. When I go to a different virtual desktop, the Browser and MailNews windows disappear, even from the taskbar (unlike what happens when they are minimized). Chatzilla remains open with chrome but no content other than the tab name (as if nothing had ever been displayed: perhaps this is a different bug), even after /clear. Clicking the window buttons in the Chatzilla statusbar restores the browser and mailer window with all their current tabs... until I move again to a different virtual desktop. Moving Browser or Mailer to a non-current virtual desktop also makes them disappear. Using: openSUSE Linux 11.4 Display manager (to log in to X11): KDE4 Window manager (after logging in to X11): Gnome (Metacity, I think). If bug 476558 or bug 372650 had recently been FIXED, I'd say: check if they didn't introduce the regression. But they are still open...

... the info about status bits at bug 476558 comment #7 sounds like something that might be relevant.

Not sure why I'm CCed on a Linux bug... I don't see anything relevant in the mozilla changelogs. Does this also happen to Minefield or whatever it's called these days. Also does this happen with Gnome as the window manager.

Update: This also happens in message-compose windows, with the additional problem that they have no statusbar button. To recover them, the Window menu must be used.

In reply to comment #2: I thought you might have some notion of what could have caused this regression. This *is* the Gnome window manager, as follows: - init starts the kdm service as part of runlevel 5 (multiuser with network and X11) - kdm starts X and also a second instance of kdm - The user gets a login window to X11 where he can select a username, type in a password, and optionally change the window manager from the latest one used by that login name - My "current default" window manager is Gnome. Once my login is accepted, it opens with my 20 virtual desktops, my desktop wallpaper, and whatever apps it remembers from my latest X logout (not Mozilla apps which I close manually before logging out of X) The bug does not happen with the current Nightly nightly, as follows: Mozilla/5.0 (X11; Linux x86_64; rv:6.0a1) Gecko/20110418 Firefox/6.0a1

Minimizing an affected window (via the _ button near the right end of the titlebar) makes it disappear from the taskbar after a second or two. Also shading by double-clicking the titlebar. All those "invisible" windows are present in the Window menu, can also be reopened by a statusbar button if there is one, but neither the taskbar nor the Alt-Tab widget knows about them.

Mozilla/5.0 (X11; Linux x86_64; rv:7.0a1) Gecko/20110525 Firefox/7.0a1 SeaMonkey/2.2a1pre ID:20110525003002 I don't see the bug in this build.