gnome window list panel item flickers in vertical orientation

[Cay Horstmann]

In Gutsy RC1, make the panel vertical (on left), then add a window list panel gizmo. After some time (and I haven't figured out what triggers it), it flickers like crazy, making the panel unusable. This is different from https://bugs.launchpad.net/bugs/150268 which merely complains about the icons being small.

The window list works ok with a horizontal panel, but why would any right-thinking person use that? I have a few pixels to spare on the left or right, but I want the full vertical extent on a landscape monitor/laptop screen.

[Sebastien Bacher (seb128)]

Thank you for your bug. Could you try to list easy steps to trigger the issue?

[Cay Horstmann (cay)]

Sure.

1) Open a few windows. I have ten open right now: 6 Firefox, 1 terminal, 1 OpenOffice, 1 Eclipse, and 1 Adobe Reader.
2) Right-click on Panel. Select Properties ->General -> Orientation -> Left
3) Right-click on Panel. Select Add to panel -> Window List -> Add.
4) The flickering started immediately.

It turns out not so easy to get rid of the window list. I managed to right-click and select Orientation -> Top, but it still kept flickering like crazy. pkill gnome-panel did the job. Then I was able to remove the window list and change the orientation back to left.

FWIW, uname -a reports Linux thinkpad-x60 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686 GNU/Linux. This is now the final version of Gutsy.

[Pedro Villavicencio (pedro)]

That works fine here, which video card do you have? Do you have the visual effects enabled? Does it happens without it?

[Cay Horstmann (cay)]

Thanks for checking!

I don't have special effects enabled. It is with the Intel 950 adapter, using the intel (modesetting) driver.

I hadn't tracked this for a while since I switched to the window selector applet so I could get my work done. I just tried the window list again, and the problem seems to have gone away. I'll switch back to the window list now, and if the problem recurs, I'll post another message. If not, I suppose this should be closed.

[Cay Horstmann (cay)]

Well, it was calm for a while, and then out of a sudden, it started flickering like crazy again. I wish I knew what triggered it. I tried closing applications until only a shell and browser windows remained, but that didn't stop the flickering.

[Cay Horstmann (cay)]

Just for the heck of it, I took a Wink capture.

[Cay Horstmann (cay)]

This may be a duplicate of https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/162134

[Carey Underwood (cwillu)]

I'm seeing the same issue with nvidia and radeon chipsets.

Add new panel, setting the orientation to "Left" or "Right, the size to 100 pixels, and selecting "Expand".
Add Window List applet (or drag original Window List applet to the new panel)
Set properties on Window List to "Never group windows" (grouping windows hides the problem somewhat)
Open at least 7 windows (terminals for instance); the applet seems to work fine if there's only 6 windows showing.

You will see either one or two columns of buttons in the window list. The layout changes once in a while when switching between windows (without opening new ones). The desired behaviour is a single column unless the entire available space for the list is used up.

Click and hold on a button in the window list. While holding the mouse button down, the applet will rapidly switch the layout between one and two columns. Clicking at any point where the 7th or greater button is (counting top-down) will not switch the window.

[Carey Underwood (cwillu)]

When 6 or fewer buttons are visible, the broken behaviour changes: the buttons switch between a normal consistent tab height, and what appears to be a height that dynamically changes to fill about a third of the taskbar (i.e., 4 buttons stretch to fill the space used by the 2 column layout mentioned above).

[Carey Underwood (cwillu)]

I'm experiencing this issue on the following configurations: intel chipset with compiz running gutsy; different intel chipset with metacity under gutsy; radeon 9250 with metacity under gutsy, nvidia 73005GT with compiz and metacity under gutsy and hardy.

Under feisty, the window list buttons dynamically resize to use all the available space, and don't seem to have the flickering issue (at least up to 12 windows). However, the button heights are very large until you have a large number of windows open, which is rather ugly.

[Carey Underwood (cwillu)]

I'm suspecting the problem is in libwnck rather than gnome-panel.

[Sebastien Bacher (seb128)]

could you try if that's still an issue in hardy?

[Cay Horstmann (cay)]

Yes, the behavior in Hardy is exactly the same as in Gutsy.

[Sebastien Bacher (seb128)]

could somebody having the issue send that on bugzilla.gnome.org? I don't get the bug on my hardy installations

[Pedro Villavicencio (pedro)]

I don't get the bug either, since nobody has answer I'm closing this bug for now, feel free to reo pen it if you send it upstream, thanks.

[Carey Underwood (cwillu)]

Sebastien/Pedro, I can duplicate from a hardy live cd. The steps I listed above should be sufficient to duplicate, although make sure you have 'group windows' disabled, otherwise you have to open 7 distinct applications rather than 7 copies of (say) gnome-terminal.

[Carey Underwood (cwillu)]

http://bugzilla.gnome.org/show_bug.cgi?id=86382 is the upstream bug (or rather, issues with the fixing of that bug caused this, discussed starting around comment #50.)

[Pedro Villavicencio (pedro)]

ok, thanks so this is a duplicate of bug 43066, marking it as such.