Gnome Window Selector loses windows

[Robert Lange]

The package that this is reported against contains the Gnome Window Selector applet. I do not know what package that is. It would be very helpful if someone in the know set the bug to point to the correct package.

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To reproduce:

1) Open a bunch of windows of different applications in Gnome.
2) Click the Window Selector to open the menu. You should see all of your windows listed in the menu.
3) Without clicking other windows, click the Window Selector again to close the menu.
4) Without clicking other windows, click the Window Selector again to open the menu. With some probability p where 0 < p < 1, one or more of your windows will be missing from the list.

Once missing, this window(s) will continue to be missing from the list until you change focus to another window. Then, the next time you click the Window Selector once, you should see all windows listed again. (Effectively, you are back to step 2.)

I have noticed this bug only in the last week, so I don't know if a recent update triggered it, or if it has been around for a while and I merely did not notice it before now.

This bug is kind of a phantom, as sometimes I cannot trigger it and sometimes it happens repeatedly. I have not found a sequence of actions that guarantees repeatability, but if I use the desktop for a while, the bug does occur relatively frequently.

I should stress that the windows themselves do not disappear, only the listings of the windows in the Window Selector list.

There is a workaround. Changing window focus a few times seems to put missing windows back on the list. On at least one instance, all of the windows disappeared from the list and I needed to open new windows to bring the existing windows back on the list.

This bug is quite annoying because I do not use the Window List applet and the Window Selector is my primary method for switching windows.

[Robert Lange (rcl24)]

This bug occurs on Ubuntu 7.10. I also use Debian Etch at work and I do not believe I have ever seen this bug occur on Etch.

[Robert Lange (rcl24)]

On further experience, I have found that once a particular window has been "lost", that window seems to be the most likely to become lost again.

For example, I have a terminal window, an Emacs window, and a browser window open. The Terminal window gets lost. I change window focus to another window and now, on the next click-open, the Window List shows all windows. Then I click it closed and open again, and with very high probability (p = 1?), the Terminal window will get lost again.

Once I close the terminal window, the list appears to work properly. I can open a new terminal window, and the list continues to work properly. I still have no idea what triggers a window getting lost in the first place.

[FlimFlamMan (lists01)]

I have this same issue on two machines, one nvidia and one ati. It only occurs when desktop effects are enabled.

[Tim Habigt (narfg)]

Added package information.

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please answer these questions:

 * Is this reproducible?
 * If so, what specific steps should we take to recreate this bug?
 * What ubuntu version do you use?

 This will help us to find and resolve the problem.

[Robert Lange (rcl24)]

The bug occurred in Gutsy definitely. I used Hardy only very briefly, so I don't know if it occurred there. Right now I have no dedicated Linux box, due to massive (hardware?) instability on what was once my primary workstation. I will not have time to correct this situation for several weeks. Once I get the workstation working, I will test with the latest (probably Intrepid at that point) and let you know if the bug is still around.

One thing worth repeating is that this *only* happened with Desktop Effects, aka compiz, activated. When using the regular Metacity window manager, I didn't see this bug.

As stated in the initial bug report, this bug is not deterministically reproducible, but if I use the desktop for any length of time, I will see it with high probability. The only thing the original summary was missing was the requirement to use Desktop Effects.

Once you see the bug for the first time, the steps described in the initial report are a pretty high probability way of seeing the bug.

[Sebastien Bacher (seb128)]

did you try on intrepid?

[John M (jwmwalrus)]

This particular bug is still present in Intrepid. The steps to reproduce (the same ones given above) are:

* Make sure visual effects are enabled
* Add the window selector applet to a panel
* Open a bunch of windows of different applications
* Click the Window Selector to open the menu (all of the windows should be listed)
* Click the Window Selector again to close the menu
* Click the Window Selector again to open the menu (some, not all, of the windows should be listed).

...:~$ lsb_release -rdc
Description: Ubuntu 8.10
Release: 8.10
Codename: intrepid

...:~$ apt-cache policy libwnck22
libwnck22:
  Installed: 2.24.1-0ubuntu1
  Candidate: 2.24.1-0ubuntu1
  Version table:
 *** 2.24.1-0ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

...:~$ apt-cache policy libwnck2.20-cil
libwnck2.20-cil:
  Installed: 2.20.1-2ubuntu4
  Candidate: 2.20.1-2ubuntu4
  Version table:
 *** 2.20.1-2ubuntu4 0
        500 http://us.archive.ubuntu.com intrepid/universe Packages
        100 /var/lib/dpkg/status

...:~$ apt-cache policy libwnck-common
libwnck-common:
  Installed: 2.24.1-0ubuntu1
  Candidate: 2.24.1-0ubuntu1
  Version table:
 *** 2.24.1-0ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

[Sebastien Bacher (seb128)]

the wnck task is enough there

[Sebastien Bacher (seb128)]

the bug should be sent to bugzilla.gnome.org by somebody having the issue

[Marty (marty-supine)]

This bug is still present in Maverick.

Reproducible always by:

- click on "Window Selector" applet to show the list
- click on it again to hide it
- click on it again to show the list
- there will be about 30% of windows missing from the list
- this error persists until focus is shifted to a different window from where it was when you started

It only presents itself when the "Appearance" setting is "Normal". Switching to "Extra" means it is no longer reproducible.

[Robert Lange (rcl24)]

I can't mark it "won't fix", but that's basically what this bug is. With the transition to either Gnome Shell or Unity, this bug is mooted. I don't think anyone is still doing any hard hacking on the old Gnome 2 stuff like this, so for anyone stuck on Gnome 2, I guess they will have to live with it.

[Thomas Hotz (thotz-deactivatedaccount)]

Does this bug happen on Ubuntu 10.04 LTS?

[icewater (a-ubuntu)]

I have since moved on to Unity - don't know if it occurs on 10.04.

[Robert Lange (rcl24)]

The bug did occur on 10.04 with the desktop visual effects turned on. However, unless Ubuntu devs plan to go back and fix an obscure bug on a non-default desktop widget that is no longer even available the current UI environment, I would ask that they mark this as "Won't fix" so that I (and others) can retire this bug from my active bug tracker.

[Thomas Hotz (thotz-deactivatedaccount)]

Ubuntu 10.04 LTS is EOL on the desktop on May, 9th 2013, so closing.