Bug 378168

Summary: Auto-hidden panel sometimes doesn't appear
Product: [Plasma] plasmashell Reporter: Maximilian Böhm <mabo>
Component: PanelAssignee: Plasma Bugs List <plasma-bugs>
Severity: normal CC: aleixpol, mabo, nate, niccolo.venerandi, notmart, notuxius
Priority: NOR    
Version: 5.9.4   
Target Milestone: 1.0   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Maximilian Böhm 2017-03-27 17:24:05 UTC
I have a side panel that frequently does not show up when I'm hovering the mouse on the screen border. The panel is configured to automatically disappear. It works flawlessly with new sessions but with older sessions – I can't say what is triggering this – suddenly it just stops appearing again. The only workaround to get it show up again is to open the monitor settings and to switching the primary screen from none to this one (I have just one monitor).
This annoying behaviour is nothing new, I've had this with any Plasma 5 release.
Comment 1 Alexander Mentyu 2018-03-02 11:59:07 UTC
Looks related to https://bugs.kde.org/show_bug.cgi?id=376031
Comment 2 Maximilian Böhm 2018-03-02 15:07:00 UTC
Indeed. And still an issue on Plasma 5.12.
Comment 3 Nate Graham 2022-06-25 17:17:41 UTC
Is the panel on a screen edge that has another monitor on the other side of it?

A lot has changed since this bug was filed. Is it still reproducible for you in Plasma 5.24 (the latest LTS version) or 5.25 (the latest version, period)?
Comment 4 Maximilian Böhm 2022-06-25 23:30:38 UTC
This bug is still occurring with Plasma 5.25.1. As described in my report, I only have one active monitor. But there is a second output configured (AV-Receiver) which is deactivated most of the time. But it makes no difference where I position this second output, I’m still losing my side panel from time to time. This has nothing to do with the second output being activated, it happens just out of nowhere in sessions with deactivated second output. X.org.
Comment 5 Nate Graham 2022-06-27 16:02:33 UTC
Thanks. Sounds like the panel is being moved over to the other output, and you can't see it there because the output is off. Can you help me verify this theory?

Right-click on desktop > click "Enter Edit mode" > in the Edit Mode toolbar at the top of the screen, click on "Manage Desktops and Panels". A window will appear. In that window, see if the panel has gotten moved to the other screen (From there, you can also move it back).
Comment 6 Maximilian Böhm 2022-06-27 22:35:14 UTC
Good idea but no… The "Manage Desktops and Panels" window displays my panel on my primary screen. When I drag it to another (disabled!) screen, it quickly appears on the primary again, to immediately disappear. When I drag it back to my primary screen, it is again there and appearing on mouse pointer hovering like it should.
Comment 7 Nate Graham 2022-06-27 22:46:08 UTC
So the window shows your panel on the screen it's supposed to be on, but it's not actually visible? Sounds like it's not related to the issue I was thinking of.

Does this happen if you set your panel to be always visible instead of auto-hide?
Comment 8 Maximilian Böhm 2022-06-27 23:25:01 UTC
Does not happen to always-on panels. This info was contained in my original bug report title.
Comment 9 Nate Graham 2022-06-28 16:04:40 UTC
Oops, sorry.

When this is happening, and you move your cursor towards the edge that the auto-hidden panel lives on, do you see the normal glow effect or not?
Comment 10 Maximilian Böhm 2022-06-28 23:09:22 UTC
No, no glow effect when the panel is lost.
Comment 11 Nate Graham 2022-06-29 15:43:12 UTC
OK, that suggests to me that the issue could be in KWin.

When this happens, do any other screen edge/corner effects also not work? Or is it just the panel auto-hide that gets broken?
Comment 12 Maximilian Böhm 2022-06-30 21:50:25 UTC
It’s not affecting my screen corners for Kwin actions.
The side panel I’m talking about is on the right side of my screen.
Tried now to also auto-hide my main panel on the bottom: Interestingly, it‘s not affected when my side panel doesn’t shows up again: The panel on the buttom comes back every time, at least in my testings for a day.
Comment 13 Bug Janitor Service 2022-07-15 04:36:53 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 14 Maximilian Böhm 2022-07-15 13:40:50 UTC
Dear Bug Janitor Service,

I have already provided the needed info in my comment on June 30.!
Comment 15 Nate Graham 2022-07-15 21:56:27 UTC

No idea what to do with this.
Comment 16 Maximilian Böhm 2022-07-15 23:23:16 UTC
You could try to reproduce this bug with a auto-hidden side panel second to your main panel.
It needs a while here, but over most of days, just at one point it stops appearing again.
Comment 17 Nate Graham 2023-09-18 17:23:06 UTC
I still cannot reproduce this in any capacity at all except for when the panel is on an edge between screens. Are you still able to reproduce it? If so, are you able to narrow down the circumstances under which it happens? I'm afraid a totally random bug that developers can't reproduce isn't going to be actionable. Thanks in advance for your help!
Comment 18 Maximilian Böhm 2023-09-19 00:47:00 UTC
"except for when the panel is on an edge between screens" is correct in my case. BUT I have the right screen deactivated most of the time (AV reciever just for HDMI audio) and this happens nonetheless. Yes, it’s still occurring, at random.
Comment 19 Nate Graham 2023-09-19 16:00:21 UTC
In that case, this does appear to be Bug 351175, with the specific trigger being the fact that your HDMI AV receiver is inappropriately detected as a monitor, which is Bug 473685. The fact that it happens randomly would be due to the particularities of how Bug 473685 manifests.

As a workaround, you should be able to use the KScreen KCM to re-arrange the (non-existent) screen for your AV received to be on another screen edge.

*** This bug has been marked as a duplicate of bug 351175 ***
Comment 20 Maximilian Böhm 2023-09-19 18:43:43 UTC
Hm… I will try the workaround. But I have issued this bug report in 2017, when you still could position a screen *into* another, which I did to prevent the annoying AVR 'monitor' to show up in the Desktop Grid effect.
Comment 21 Nate Graham 2023-09-19 18:52:39 UTC
You still can do that, though the drag area is rather small. This makes the screens count as being mirrored internally.
Comment 22 Maximilian Böhm 2023-09-19 20:37:36 UTC
(In reply to Nate Graham from comment #21)
> You still can do that, though the drag area is rather small. This makes the screens count as being mirrored internally.

Where do I have to drag? The screen always just moves around the primary monitor.
Comment 23 Nate Graham 2023-09-19 20:38:46 UTC
Right into the very center of the screen you want to be mirrored with the screen you're dragging. Like I said, it's pretty fiddly.
Comment 24 Maximilian Böhm 2023-09-26 18:29:49 UTC
You were right, my auto-hidden side panel has stopped to not-coming-back after rearranging the position of the AVR screen.
Comment 25 Nate Graham 2023-09-26 18:36:40 UTC