Toggling Compiz plugins turns Unity panel black/corrupt

Any workaround? The only thing that helps is logout/logon.

This bug affects me, too.

Unchecking a checkbox in CompizConfig Settings Manager makes the Unity panel disappear. It may turn black or various kinds of things. I've made some screenshots:

http://img691.imageshack.us/img691/984/panelgone1.jpg
http://img715.imageshack.us/img715/1350/panelgone2.jpg
http://img101.imageshack.us/img101/2972/panelgone3.jpg
http://img707.imageshack.us/img707/9295/panelgone4.jpg

Logging out and in again restores the panel.

On 29/04/2011 21:35, aka wrote:
> Any workaround? The only thing that helps is logout/logon.
>

Workaround is to run "unity --replace", which restarts Unity.

I'm marking this bug as confirmed, since I'm not the only one experiencing it.

  affects unity
  status confirmed

  affects ubuntu/unity
  status confirmed

--
Kind regards,
Loong Jin

Yet another confirmation. Experienced the same when playing around with ccsm. Issuing the workaround command restores unity panel to its former state.

Same issue here with an Nvidia GeForce FX 5200 card and the nouveau driver enabled. I did not change anything within the compiz manager, just freshly installed Ubuntu 11.04. The side panel remains black, but the applications are clickable. Resetting Unity with "unity --reset" does nothing. When switching to Unity 2D the panel works fine. I have added a picture.

It appears the problem might be that the Unity plugin is being tricked into creating additional panels when they're not needed. And possibly getting the stacking order wrong too.

There are two pieces of evidence for this:
  1. The panel shadow gets darker when it's corrupt, suggesting multiple panels are present.
  2. This command starts showing multiple results instead of just one when the corruption occurs:
         xwininfo -children -root | grep panel

Sorry, a more accurate way to count the number of Unity panels running is something like this:
for i in `xwininfo -root -children | awk '/^ *0x/ {print $1}'`; do xwininfo -id $i -all | grep '"panel"'; done

When the panel is corrupt, you can see many matches. But I think there should only be one. The same goes for when you replace "panel" with "launcher" in the above command. It appears both are being leaked by the Unity plugin.

As it happens, Loic put a comment in the relevant code acknowledging a leak was present:
unity/src/PanelController.cpp: // FIXME(loicm): Several objects created here are leaked.

Are we all just seeing side-effects of said leaks?

Fixed, but yet to be merged. See Related branches above.

Also, the fix will be available for testing soon in ppa:vanvugt/unity (https://launchpad.net/~vanvugt/+archive/unity)

Daniel, your version seems to crash unity when I enable/disable a plugin and it is not auto respawned neither.

Thanks Omer. I didn't notice the crash because mine was either respawning correctly or not crashing.

Predictably, valgrind is showing the crash is located in the UnityScreen destructor chain. That's code that has never been tested because until now it was leaking and never being destructed correctly. :)

I shall have a look and try to make it all part of the fix for this bug.

See also: bug 758248

@Omer: I have fixed the crash but this showed me that the corruption is actually not fully fixed.

Still, the new version which doesn't crash, and has much less corruption, is now building in my PPA (unity 3.8.12-0ubuntu1vv4).

Also, I am no longer claiming to have fixed "megabytes" of leaks with this fix. I only thought that because my compiz was respawning and I was deceived by the size. Any memory leaks not directly causing the window/resource leaks that cause the corruption in this bug will be dealt with as separate bugs. That will keep the final fix for this bug to a minimum size and not interfere with other people working on unity/nux leaks right now.

OK, the final fix is in nux only. Those previous leak fixes to unity are actually not required to fix this bug so I will separate them.

Sadly, because the fix in nux requires an API change to be synchronized with unity, it means I can't put the fix in my PPA for you right now. You can only test the fix in the next release of the libnux packages. Assuming the merge proposal is accepted and cherry-picked...

An alternate fix has now been proposed for natty. You can test it using: ppa:vanvugt/unity (https://launchpad.net/~vanvugt/+archive/unity)

The fix was committed in lp:nux r356 (https://code.launchpad.net/~unity-team/nux/trunk)

A compatible, and trivial, fix for natty was committed in lp:nux/0.9 r351 (https://code.launchpad.net/~unity-team/nux/0.9)

Still waiting for it to me cherry-picked.

Someone, please cherry pick the one line fix from lp:nux/0.9 (r351)

Still no improvemt with the "unity black panel bug" on my machine with a Nvidia GeForce FX 5200 card. The panel is still black, yet transparent with an application running under it, and the programs are still clickable and popups are showing (see image). It would be nice though to actually see, what you click :-) I have now unity 3.8.14 installed and the Nouveau graphic driver enabled (as the Nvidia driver still does not seem to be activateable through jockey in Natty). At least Daniel van Vugt's command shows that there really seem two panels to be running above each other:

0x3200003 "panel": () 1920x24+0+0 +0+0
0x1c00003 "panel": () 1920x24+0+0 +0+0

Hopefully the right patch will soon be in the Natty repositories. Keep up the good work!

@André: Your screenshot shows you are experiencing bug 762478 which seems to be a common problem for Geforce FX owners. Also, that is the Launcher on left hand side. The Panel is the bar at the top of the screen.

Fix was released in nux (1.0.2-0ubuntu1) oneiric, after being committed to lp:ubuntu/oneiric/nux r33.

Fix was released in nux 1.0.1, after being committed to lp:nux r356.

A fix for natty is likely to appear in the next natty-update of libnux-0.9-0, but not certain. I don't see an update being planned yet, but it is already in the parent branch lp:nux/0.9.