Bug 336570 - Task list not updated in multiscreen setup
Summary: Task list not updated in multiscreen setup
Status: RESOLVED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Task Manager and Icons-Only Task Manager (show other bugs)
Version: master
Platform: Exherbo Linux
: NOR normal
Target Milestone: 1.0
Assignee: Eike Hein
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-06-22 09:52 UTC by Bernd Steinhauser
Modified: 2016-06-16 23:18 UTC (History)
4 users (show)

See Also:
Latest Commit:
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Description Bernd Steinhauser 2014-06-22 09:52:59 UTC
When running a multiscreen setup with one panel (containing a task manager) on each screen, it can happen, that one of the task managers stops updating the containing window list, when the option "Show only tasks from the current screen" is selected.

Reproducible: Always

Steps to Reproduce:
1. Configure a multiscreen setup with a panel on each screen, ensure that each panel has a task manager
2. Ensure that "Show only tasks from the current screen" is deactivated for both
3. Select the mentioned option for task manager 1.
4. Open some windows and drag them from one screen and backwards. Everything should be fine
5. Select the mentioned option for task manager 2.
6. Everything should still be working
7. Deactivate the option for task manager 1.
8. Drag some windows around, task manager 2 has stopped working properly.
Actual Results:  
The task manager that shows only the windows of the current screen will stop working properly, the window list isn't updated anymore.

Expected Results:  
Should still work.

Clicking windows still works. The task manager also shows which window is activated, has focus etc. It's only the list of windows that isn't updated.
Comment 1 Eike Hein 2014-06-22 09:58:30 UTC
I don't have a multiscreen setup, can someone confirm?
Comment 2 Eike Hein 2014-06-22 10:00:35 UTC
Adding Luca and Aleix to CC since they've been involved with TM multi-screen stuff in the past.
Comment 3 Luca Beltrame 2014-06-22 10:10:12 UTC
I only use "Show only from current screen" so that's why probably I didn't notice it. However, after trying (assuming I got the steps correctly) I can't reproduce it.
Comment 4 Bernd Steinhauser 2014-06-22 11:16:48 UTC
(In reply to comment #3)
> I only use "Show only from current screen" so that's why probably I didn't
> notice it. However, after trying (assuming I got the steps correctly) I
> can't reproduce it.
I use that option as well, so I didn't notice instantly.

For me, it makes a difference if I go from both deactivated to one activated (which works) or from both activated to one deactivated (which doesn't work).

I should maybe note, that I don't use the kscreen kcm to setup my screens, but a simple xrandr command, since kscreen is broken for me (see bug 325277):
xrandr --output HDMI-0 --auto --primary --output VGA-0 --right-of HDMI-0

Don't know if that makes a difference regarding kscreen.
Comment 5 Bernd Steinhauser 2014-06-22 19:56:53 UTC
I just tried with the project neon live cd and was able to reproduce the bug there with the steps outlined above.

Since I guess the live cd uses a clean config and since the binaries come from a completely different distribution, I think it is save to say that this isn't restricted to my system.
Comment 6 Aleix Pol 2014-06-23 15:05:38 UTC
Hi, I just created a plasmoid [1] that just shows the screen name. We can use this to figure out in what containment the plasmoid thinks it is, so we can rule out whether it's a bug in plasmashell.

[1] git clone kde:scratch/apol/plasma-screentest
Comment 7 Bernd Steinhauser 2014-06-23 18:49:10 UTC
Not sure if that helps, since assigning the windows to the respective task managers works in principle.

Tried it though and it shows 0 for the primary screen and 1 for the other one.
Comment 8 Luca Beltrame 2014-07-05 19:01:24 UTC
Following up as I reproduced, at last. Tasks are indeed in wrong positions, 
because screen 1 is not properly updated and shows stuff from screen 0 instead 
(which is the primary).
Comment 9 Luca Beltrame 2014-07-05 19:03:27 UTC
In data sabato 05 luglio 2014 21:01:17, hai scritto:
> Following up as I reproduced, at last. Tasks are indeed in wrong positions,
> because screen 1 is not properly updated and shows stuff from screen 0
> instead (which is the primary).

Scratch that, I was using some old configuration: after removing and adding 
the task manager, it behaves.
Comment 10 Luca Beltrame 2014-07-06 12:29:45 UTC
> Tried it though and it shows 0 for the primary screen and 1 for the other
> one.

Following up yet again: on startup the task manager shows tasks from the wrong 
screen (ie. tasks from screen 0 where it should be screen 1). If removed and 
readded, it works, but *only* for the session. Upon logout / login, the 
problem manifests again.
Comment 11 Bernd Steinhauser 2014-07-07 20:45:00 UTC
Not sure if I fully understood that. For me, it is still reproducible, if I perform the steps outlined above. Also, the screen number (or primary state) does not matter for me, it works either way.
Comment 12 Luca Beltrame 2014-07-07 22:17:54 UTC
> perform the steps outlined above. Also, the screen number (or primary state)
> does not matter for me, it works either way.

Just FYI: I noticed that you can force the task list update this if you move 
the panel to another screen, then back to the original one.
Comment 13 Aleix Pol 2014-11-24 16:47:53 UTC
Seems to be working here, I'll assume it's been fixed since July.
Comment 14 Bernd Steinhauser 2014-11-29 09:55:04 UTC
No, it still behaves the same way with current plasma head (and kf 5.4), so at least for me, it is not fixed.
Can you please check, if you followed the steps outlined above?
Comment 15 Bernd Steinhauser 2014-12-07 08:13:23 UTC
Also checked for current KF5 master.
Comment 16 Eike Hein 2015-05-19 13:33:16 UTC
Bug 346878 might be related.
Comment 17 Christof Kaufmann 2016-02-17 16:17:33 UTC
I can confirm this bug in Kubuntu 15.10 with Kubuntu Backports PPA (but libtaskmanager5 is Version 4:5.4.2-0ubuntu1). It happens occasionally, when I switch to two screen mode. However, I can also confirm that the workaround described in bug 268259, comment 43 and restarting plasmashell helped. So they seem to be related (and so bug 346878). I wonder if the OP can still confirm the bug, as it should have been resolved in bug 268259, comment 50 as far as I can see and that was for version 5.3.
Comment 18 Bernd Steinhauser 2016-02-18 04:23:36 UTC
I didn't really try this, because multiple panels for me caused massive performance issues (opened a bug for that), so I couldn't use them.

Now that you mentioned it, I tried again at it seems to work for me, so somehow it got fixed, I guess. Didn't try for long, though.
Comment 19 Bernd Steinhauser 2016-02-19 16:49:45 UTC
Ok, was a bit fast there. I missed, that you have to come from the side of showing only tasks from the current screen on all screens featuring a task list.
It does work if you let one stay with the feature deactivated and only activate for one of them.
As soon as you activate it for both (or all of them) and then change it back, it starts to go wrong.
Comment 20 Eike Hein 2016-06-16 23:18:35 UTC
Plasma 5.7 ships a fully-rewritten Task Manager backend which should resolve these issues. Note that the multiscreen code currently has further improvements under review that are not yet in 5.7 Beta. Please re-test with the Plasma 5.7 final release and feel free to reopen if problems do persist after all.