Bug 427197 - Wrong computation of primary screen and panel on X11
Summary: Wrong computation of primary screen and panel on X11
Status: RESOLVED DUPLICATE of bug 426496
Alias: None
Product: plasmashell
Classification: Plasma
Component: generic-multiscreen (show other bugs)
Version: 5.19.5
Platform: Manjaro Linux
: NOR normal
Target Milestone: 1.0
Assignee: Aleix Pol
Depends on:
Reported: 2020-10-01 10:42 UTC by elman
Modified: 2020-10-06 18:24 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:

maximized window (187.61 KB, image/png)
2020-10-01 10:42 UTC, elman

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Description elman 2020-10-01 10:42:05 UTC
Created attachment 132042 [details]
maximized window

I have 2 displays. Notebook internal and external. Both are 4K and both are using 2.0 scaling. I have set my external screen as primary. And they are configured so that external is above internal.

Now when I start my notebook and connect external screen, panel is correctly shown on external (primary) screen. However when I maximize window on external screen, it's height is 2160 px and not (2160px - panel height) so part of the window is painted under panel. 

When I maximize window on notebook display, its height is (2160px - panel height) and not 2160px so window doesn't fill whole screen.

See screenshot.

If I go to setting, select notebook screen as primary, click apply and then select external screen as primary, all computations are correct.

I have also seen this issue on Kubuntu 20.04 with Plasma 5.18.5 (I believe).

1. Connect external screen and set it primary
2. Disconnect external screen (so internal is set as primary)
3. Connect external screen and wait for it to be configured
4. Maximize windows on either screen

Wrongly computed window height.

Correctly computed window height.

Linux/KDE Plasma: Manjaro Stable
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.73.0
Qt Version: 5.15.0
Comment 1 elman 2020-10-05 10:34:28 UTC
I have also seen similar problem on Arch. I have 1920x1080 notebook display and 1920x1200 external display. I have set external display as primary. On logging into plasma, external display is correctly set as primary, however it display wallpaper of size 1920x1080 on 1920x1200 and right click only works on wallpaper - e.g. right click doesn't work at the bottom of the screen.

When I go to settings, set internal display as primary and then external as primary, wallpaper is set 1920x1200 and I can right click on whole area.
Comment 2 Nate Graham 2020-10-05 21:26:09 UTC
Are you sure you're using Qr 5.15.0, or is it 5.15.1? I ask because 5.15.1 regressed this recently.
Comment 3 elman 2020-10-06 07:31:26 UTC
Arch has 5.15.1 and it seems yesterday's update fixed it. I made 2 restarts and displays configured correctly. When I look at log I see this possibly relevant packages upgraded:
[ALPM] upgraded qt5-base (5.15.1-1 -> 5.15.1-3)
[ALPM] upgraded qt5-webengine (5.15.1-2 -> 5.15.1-3)
[ALPM] upgraded plasma-workspace (5.19.5-1 -> 5.19.5-3)
[ALPM] upgraded plasma-wayland-session (5.19.5-1 -> 5.19.5-3)

I will check Manjaro and Kubuntu, when I get home.
Comment 4 Nate Graham 2020-10-06 14:36:40 UTC
Sounds like Bug 426496 then. Thanks.

*** This bug has been marked as a duplicate of bug 426496 ***
Comment 5 elman 2020-10-06 17:40:16 UTC
Manjaro has Qt 5.15.1 so it will be fixed with next update.
However Kubuntu has Qt 5.12.8. Do you think same bug is also present over there?
Comment 6 Nate Graham 2020-10-06 18:24:45 UTC
No. The regression was introduced with Wt 5.15.1.