Bug 356727

Recorded screen session that shows the problem:
http://stewie.be.tintel.eu/kde_bug356727/out.ogv

In this case I got lucky, the panel reappeared at the top of the external monitor, after unplugging and replugging it: http://stewie.be.tintel.eu/kde_bug356727/dualafterunplugreplug.png

Guess I wrote that comment too soon. Usually when the panel reappears, it is still in a wrong location, but then I can drag it to where it should be, without it disappearing. Currently I am stuck in a loop, dragging it from top of external monitor to bottom makes it disappear as soon as it reaches the other monitor. Unplug/replug -> back on top of external monitor. Repeat.

After unplugging and replugging several times and always ending up in the same situation, I logged out and back in. The panel was still at the top of the external monitor, but this time I was able to drag it down without it disappearing.

Please give this bug the priority it requires. Using Plasma 5 with multiple monitors is currently almost impossible. Running into this problem on a daily basis is getting very frustrating and is really killing productivity.

*** Bug 357249 has been marked as a duplicate of this bug. ***

Can you attach your ~/.config/plasmashellrc

and ~/.config/plasma-org.kde.plasma.desktop-appletsrc please

Created attachment 96328 [details]
plasmashellrc

Created attachment 96329 [details]
desktop-appletsrc

Please note that after killing plasma I could no longer reproduce, so it's probably something not too trivial.

Thanks. I have a theory but I don't have two monitors here at the moment to test.

When you dragged it and it disappeared was the other monitor 768 px tall?
and now it's a different size?

Created attachment 96330 [details]
plasmashellrc

My .config/plasmashellrc - not changed since 12/12, before I reported this bug

Created attachment 96331 [details]
plasma-org.kde.plasma.desktop-appletsrc

My .config/plasma-org.kde.plasma.desktop-appletsrc - last modified today

Created attachment 96332 [details]
.config/plasma-org.kde.plasma.desktop-appletsrc.M14439

My .config/plasma-org.kde.plasma.desktop-appletsrc.M14439 - last modified 18/12, after I reported this bug, I suspect after updating to plasma 5.5.1)

Still present in 5.5.2

This bug affects me too.

Panels also disappear when changing which monitor is the default monitor (and reappear when I physically plug/unplug the second monitor)

I also experience this. I have an external monitor usually set to be on the left side of my laptop monitor.

I experience this only when I plug in or set up after login. If I plug it in before I log in, the panel still appears on the wrong monitor, but doesn't disappear on moving it back to the laptop monitor. 
The resolutions I use are:
external monitor: 1920*1080
laptop monitor: 1366*768

(In reply to Máté Eckl from comment #16)
> I experience this only when I plug in or set up after login. If I plug it in
> before I log in, the panel still appears on the wrong monitor, but doesn't
> disappear on moving it back to the laptop monitor. 

In my case the panel appears on the Laptop screen when having the second monitor connected on login. However, I can confirm that in this case I am able to move it around between monitors.

*** Bug 353426 has been marked as a duplicate of this bug. ***

I just reproduced the problem on 5.5.3 on Arch Linux.
When I did:
kquitapp plasmashell; sleep 1; plasmashell 

The lost panel reappeared in the original place. After that I tried to move the panel again and it succeeded. So after a fresh start of plasmashell the panel can be moved

As this behaviour is now confirmed by many different users and the bug was opened more than a month ago, I wonder why its status is still "UNCONFIRMED"?

This bug in combination with thisone are pure hell - https://bugs.kde.org/show_bug.cgi?id=354386 

I attach a monitor to my laptop (in a running session).  The panel moves to the secondary monitor (see the bug link I posted), and then I cannot get it back to the first because of this bug.  If I log out, and disconnect the second monitor, log in again - it is does not  appear on the laptop screen. When I then connect the second monitor, its still there - but still cannot be moved.  The only option to get the panel back on my laptop screen is to log in with the secondary monitor connected and then move the panel to the laptop screen then log out, disconnect the second screen and log in again.

I would highly appreciate if someone looks into this, as one of the main uses of my laptop is to give presentations. With this behavior KDE 5 is not an option, as I often don't have a second monitor around, to follow above workaround to get my panel back.

Confirming bug because it affects multiple users spanning over quite a few reports which are marked as duplicates of this one (bug 353426, bug 347195). Unfortunately were the other bugs about the plasma panel generally disappearing, not only on drag & drop; I thus changed the subject to be more generic.

[Containments][76]
activityId=
formfactor=2
immutability=1
lastScreen=1 //Some times it is not change
location=3
plugin=org.kde.panel
wallpaperplugin=org.kde.image

When i change the lastscreen property and restart plasmashell i have panel again on a correct screen .

[Containments][76]
activityId=
formfactor=2
immutability=1
lastScreen=1 //Some times it is not change
location=3
plugin=org.kde.panel
wallpaperplugin=org.kde.image

When i change the lastscreen property and restart plasmashell i have panel again on a correct screen .

sorry for duplicate. I forget, it should set in plasma-org.kde.plasma.desktop-appletsrc.

I have this problem also here running Fedora 23.  I have not been able to get the default panel back, so I have had to add a new one to be able to work with the laptop. Just like cherenz@aip.de, I use the laptop to give presentations, and the disappearing panel is certainly not helping out.

Restarting plasmashell  has not helped. In the course of my tests, I have seen the newly created panel going to the external monitor, so that there were two panels there and none in the laptop screen which, by the way, is the primary output all along.

I am running Kubuntu with Plasma 5.5.3 from the backports PPA.

I can confirm this bug. Here is the behaviour for me:

I have a laptop running at 1920x1080 with the default panel.

I plug in a second monitor running at 1920x1080 and configure it to be the primary, and disable the laptop panel.  The panel moves to the external monitor.

I unplug the external monitor. The panel disappears. I plug the external monitor in again - the panel reappears.

It is a similar issue if I unify the outputs across both monitors - unplugging the external monitor makes the panel disappear, plugging it in again makes it re-appear.

Thanks

Same problem here, with 5.5.4

two monitors setup, the behaviour is a nightmare: standard panels appears and disappears when plugging on and off the external monitor; the absolute chaos is when the laptop goes in standby mode when not connected to external monitor and wakes up with two monitors. 
It also happens to have the default panels duplicated, one per screen.
Even wallpapers are swapped (that is to say, a wallpaper initially placed on external monitor, after reboot it appears on laptop screen even with the external plugged in).

Sometimes I can fix (well, improve a bit) things by logging out from kde and editing plasma-org.kde.plasma.desktop-appletsrc by changing all lastScreen=1 to lastScreen=0

I don't know if this can be related to wrong rc file creation or what else.

If needed I can provide more details or debug info or even compile with patches.

Thanks.

*** Bug 355528 has been marked as a duplicate of this bug. ***

*** Bug 358353 has been marked as a duplicate of this bug. ***

*** Bug 358624 has been marked as a duplicate of this bug. ***

*** Bug 359629 has been marked as a duplicate of this bug. ***

*** Bug 351529 has been marked as a duplicate of this bug. ***

*** This bug has been marked as a duplicate of bug 356225 ***

I have OpenSuse Leap 42.1, Plasma 5.5.2.
When I disconnet an external monitor in the laptop, and reconnect another one, I lose the taskbar.
If I reboot the laptop, I can restore it again.

How to restore it, without rebooting?

Executing this:
   kquitapp plasmashell; sleep 1; plasmashell 

solves the problem.

Created attachment 97996 [details]
attachment-3995-0.html

Not always unfortunately... sometimes a logout and login in necessary.
On 21 Mar 2016 08:47, "David P. via KDE Bugzilla" <bugzilla_noreply@kde.org>
wrote:

> https://bugs.kde.org/show_bug.cgi?id=356727
>
> --- Comment #36 from David P. <sanete@gmail.com> ---
> Executing this:
>    kquitapp plasmashell; sleep 1; plasmashell
>
> solves the problem.
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.
>

I also have the problem in Fedora 24. I have 2 monitors (HDMI + DisplayPort). When I disable HDMI output in kscreen, the taskbar disappear.

Almost every time I have 2 video outputs and I change something using Switch Display (Meta + P) the panel disspears when I reboot.
In my case I use a monitor and a TV.
I'm forced to set the output to Unify Outputs and don't change it.
I always solve it with Timeshift restoring my last system backup.

I forgot to say this has happened to me using every single Plasma version for the last 2 or 3 years. That's the time I'm using Linux.
On several computers.

Still seems to suffer from the same issue when I swap between using my 2 different laptops, both having my external monitor attached via HDMI. The external screen has a higher resolution (not sure if that matters). Oftentimes when I switch from 1 laptop to the other, and I alter the source of my external monitor (through buttons on the screen), the monitor ends up with a desktop but no KDE taskbar at the bottom. At that stage, even if I press F10 and manage to go back to 2 screens, neither of the screens will have a taskbar. That means a hard reset is the only way I know to deal with this.

*** Bug 425444 has been marked as a duplicate of this bug. ***

Definitely an issue for me. Also seems to be triggered when changing resolution on the primary monitor after disconnecting a second monitor.

Created attachment 141521 [details]
New crash information added by DrKonqi

plasmashell (5.22.5) using Qt 5.15.3

- What I was doing when the application crashed:
Connected two external displays
Bottom panel disappeared from Plasma desktop
Used system preferences to reset layout to theme defaults to force panel to reappear

- Unusual behavior I noticed:
Bottom panel disappeared from Plasma desktop until reset layout

-- Backtrace (Reduced):
#4  0x00007fd0b41a1084 in Plasma::Applet::immutability() const () from /lib/x86_64-linux-gnu/libKF5Plasma.so.5
#5  0x00007fd0b41a115d in Plasma::Applet::destroy() () from /lib/x86_64-linux-gnu/libKF5Plasma.so.5
#6  0x00007fd0a4097dc8 in SystemTrayContainer::~SystemTrayContainer (this=0x55a128ecb230, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/atomic_base.h:413
#7  0x00007fd0a4097e2d in SystemTrayContainer::~SystemTrayContainer (this=0x55a128ecb230, __in_chrg=<optimized out>) at ./applets/systemtray/container/systemtraycontainer.cpp:34
#8  0x00007fd0b210ad8e in QObjectPrivate::deleteChildren() () from /lib/x86_64-linux-gnu/libQt5Core.so.5

*** Bug 442438 has been marked as a duplicate of this bug. ***

*** Bug 347195 has been marked as a duplicate of this bug. ***

*** Bug 364512 has been marked as a duplicate of this bug. ***

*** Bug 371251 has been marked as a duplicate of this bug. ***

*** Bug 376031 has been marked as a duplicate of this bug. ***

*** Bug 377588 has been marked as a duplicate of this bug. ***

*** Bug 426886 has been marked as a duplicate of this bug. ***

*** Bug 438114 has been marked as a duplicate of this bug. ***

*** Bug 438293 has been marked as a duplicate of this bug. ***

*** Bug 438665 has been marked as a duplicate of this bug. ***

Hi guys can I confirm I have a separate issue:

-Arch
-KDE/plasma 5.23
-wayland in use
-single monitor
-AMD

after I lock the display, walk off, come back after display is sleeping, wiggle mouse, login to login window, back to the desktop the taskbar/panel is missing, pressing super key does not open it etc its just gone until restart. thats different to this issue right?

- On Fedora 35 (up to date)
- Kernel 5.15.11
- plasma 5.23.4

I have this issue after disconnecting a second monitor, taskbar disappears and meta key doesn't bring it up.

spent a little time diagnosing exactly what triggers the panel disappearing:

1) display configuration being set to "remote display".
2) disconnect HDMI

been checking the logs, and it's a bit tricky to know what is responsible exactly, if it will help I can share them?

I don't know if we should open a separate bug or not but this iss a showstopper for using KDE under Wayland:

-Arch
-KDE/plasma 5.23
-Wayland session
- external monitor (3840 x 2160) and internal monitor (1920 x 1080)

Internal monitor disabled, as soon as the external monitor gets disconnected the internal monitor gets enabled and the panel is gone. Even newly added panels are invisible but added because after restarting all the added panels are visible on internal screen and have to be removed.

(In reply to sascha.appel from comment #58)
> I don't know if we should open a separate bug or not but this iss a
> showstopper for using KDE under Wayland:
> 
> -Arch
> -KDE/plasma 5.23
> -Wayland session
> - external monitor (3840 x 2160) and internal monitor (1920 x 1080)
> 
> Internal monitor disabled, as soon as the external monitor gets disconnected
> the internal monitor gets enabled and the panel is gone. Even newly added
> panels are invisible but added because after restarting all the added panels
> are visible on internal screen and have to be removed.

You are right. as this bug says "sometimes", but our bug is always. the trigger is vague, where as ours in clear and reproducible. tell me which bug you add so I can move to that instead.

A similar thing was just fixed in Bug 447936 today; can anyone who is able to compile from source or using git master distro packages see if this issue here is also fixed for them now?

@smellymoo that exact thing should have been fixed with the fix for 447936. I'm not able to reproduce in Plasma 5.24 on Wayland no matter how I try. Can folks who have experienced this in the past try out the Plasma 5.24 beta (or Plasma 5.24 when it's released) and report back whether or not they can still make it happen?

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:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

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!

(In reply to Nate Graham from comment #61)
> @smellymoo that exact thing should have been fixed with the fix for 447936.
> I'm not able to reproduce in Plasma 5.24 on Wayland no matter how I try. Can
> folks who have experienced this in the past try out the Plasma 5.24 beta (or
> Plasma 5.24 when it's released) and report back whether or not they can
> still make it happen?

I just tried the plasma beta (plasma-desktop-5.23.90-1) and it's pretty bad:
- on second monitor the taskbar is wider than the screen
- freezes for 10+ seconds on hotswap
- most times I disconnect hdmi (while set as "only remote monitor") it then doesn't switch back to primary

but the one time that it didn't bork out, it did have a panel (when disconnecting hdmi with it set to "remote only"). Is that a win? not really, it's probably overall worse now.

can't help thinking this page is an umbrella for more than 1 bug. the bug I am experiencing is very specific and reproducible:

1) connect HDMI
2) set display config = "remote only"
3) disconnect HDMI

(In reply to smellymoo from comment #63)
> (In reply to Nate Graham from comment #61)
> > @smellymoo that exact thing should have been fixed with the fix for 447936.
> > I'm not able to reproduce in Plasma 5.24 on Wayland no matter how I try. Can
> > folks who have experienced this in the past try out the Plasma 5.24 beta (or
> > Plasma 5.24 when it's released) and report back whether or not they can
> > still make it happen?
> 
> I just tried the plasma beta (plasma-desktop-5.23.90-1) and it's pretty bad:
> - on second monitor the taskbar is wider than the screen
> - freezes for 10+ seconds on hotswap
> - most times I disconnect hdmi (while set as "only remote monitor") it then
> doesn't switch back to primary
> 
> but the one time that it didn't bork out, it did have a panel (when
> disconnecting hdmi with it set to "remote only"). Is that a win? not really,
> it's probably overall worse now.

Perhaps you could give it another go with a fresh config? I noticed that my kwinrc and plasmashellrc contain a lot of stale entries that are likely a result of the previous confused behavior.

(In reply to madcatx from comment #65)
> Perhaps you could give it another go with a fresh config? I noticed that my
> kwinrc and plasmashellrc contain a lot of stale entries that are likely a
> result of the previous confused behavior.

could you be more specific on "fresh config" do you mean wipe a folder, if so which? assuming ~/.kde/share/config/ but want to do the right one.

I have undone the upgrade to plasma beta, so I might try again when I have a minute. As it might reveal useful info for debuging this.

(In reply to smellymoo from comment #66)
> (In reply to madcatx from comment #65)
> > Perhaps you could give it another go with a fresh config? I noticed that my
> > kwinrc and plasmashellrc contain a lot of stale entries that are likely a
> > result of the previous confused behavior.
> 
> could you be more specific on "fresh config" do you mean wipe a folder, if
> so which? assuming ~/.kde/share/config/ but want to do the right one.
> 
> I have undone the upgrade to plasma beta, so I might try again when I have a
> minute. As it might reveal useful info for debuging this.

There is "~/.config/kwinrc" and "~/.config/plasmashellrc". Getting rid of at least these two and trying again might be interesting.

FWIW, I just installed plasma 5.23.90 as packaged by Arch Linux and the problem seems to gone. At least unplugging and replugging of an external display moves the panel as expected.

(I noticed a few other multiscreen issues that I wasn't getting in 5.23 but these are most likely unrelated to this)

This bug report is only about panels disappearing on screen hotplug or wake, and it sounds like that's fixed now, hooray!

If you have different issues, we'll need to track those with different bug reports. There are quite a lot of multiscreen issues, I know. :( So if I erroneously marked your bug report as a duplicate of this but you're seeing a different issue, please feel free to re-open it. Otherwise please file a new bug report. Thanks!

(In reply to Nate Graham from comment #69)
> This bug report is only about panels disappearing on screen hotplug or wake,
> and it sounds like that's fixed now, hooray!
> 
> If you have different issues, we'll need to track those with different bug
> reports. There are quite a lot of multiscreen issues, I know. :( So if I
> erroneously marked your bug report as a duplicate of this but you're seeing
> a different issue, please feel free to re-open it. Otherwise please file a
> new bug report. Thanks!

To clarify:
- The problem of erratic panel behavior seems to be gone. I tested this in a few different ways and the panel moves between screens as expected.
- Other multiscreen issues I noticed have nothing to do with the panel.

TL;DR, this bug appears to be fixed - nice job!

Fantastic!

My bug (https://bugs.kde.org/show_bug.cgi?id=438114) was marked a duplicate of this issue, but I'm still experiencing this issue with plasma 5.24 on arch. not sure if this issue is unresolved, or the original issue wasn't a duplicate.

That's a shame. It seems like the issue you were reporting is pretty much the same thing, so we may have to re-open this.

Is anyone else still experiencing the issue after upgrading to Plasma 5.24?

(In reply to Nate Graham from comment #73)
> That's a shame. It seems like the issue you were reporting is pretty much
> the same thing, so we may have to re-open this.
> 
> Is anyone else still experiencing the issue after upgrading to Plasma 5.24?

I can confirm the issue in Plasma 5.25.3. After unplugging a projector, my panel completely disappeared and I couldn't bring it back.

That's unfortunate.

It's also unfortunate that this bug report became a kind of grab-bag of related issues, which is my fault, sorry about that. As a result it would probably be best if people who are still affected could file new bug reports, and I will try my best to triage them accordingly. Thanks!

(In reply to Nate Graham from comment #75)
> As a result it would
> probably be best if people who are still affected could file new bug
> reports, and I will try my best to triage them accordingly. Thanks!

I still have this open bug report which is similar but panels move to different screens (even disabled screens sometimes):
https://bugs.kde.org/show_bug.cgi?id=453554

But the initial title doesn't exactly reflect the behavior under 5.25 because I can now recover the panels from the panel editor. Should I set a new title and set the new version number?

If the originally-reported issue no longer reproduces, but it's different in 5.25 now, then go ahead.