Bug 470185 - Maximized windows not covering entire screen in some circumstances
Summary: Maximized windows not covering entire screen in some circumstances
Status: RESOLVED DUPLICATE of bug 414522
Alias: None
Product: kwin
Classification: Plasma
Component: general (show other bugs)
Version: 5.27.5
Platform: Kubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-05-23 23:39 UTC by Aaron Kelley
Modified: 2023-06-13 21:14 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:

Attachments
Screen shot demonstrating the issue. Look at the bottom row of pixels. It is a web page in Firefox, "behind" Dolphin. (279.27 KB, image/png)
2023-05-23 23:39 UTC, Aaron Kelley 		Details
View All Add an attachment

Note You need to log in before you can comment on or make changes to this bug.
Description Aaron Kelley 2023-05-23 23:39:20 UTC 
Created attachment 159215 [details]
Screen shot demonstrating the issue.  Look at the bottom row of pixels.  It is a web page in Firefox, "behind" Dolphin.

STEPS TO REPRODUCE
1. 4K display, 200% DPI scaling.
2. Bottom panel set to "auto hide".
3. Launch Dolphin application and maximize the window.

OBSERVED RESULT
Dolphin covers the entire screen... minus the bottom row of pixels.  (See screen shot, attached.)

EXPECTED RESULT
Dolphin should cover the entire screen.

Note that snapping a window to the left or right half of the screen (i.e. Super+left arrow) does result in it covering that bottom row of pixelsproperly.  Also, this issue appears to be specific to Qt applications?  Dolphin, Kate, Konsole, and VLC will leave a row of pixels at the bottom.  Firefox, Thunderbird, Visual Studio Code and Google Earth do not.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.8
Comment 1 Nate Graham 2023-05-24 17:07:12 UTC 
Are you using Wayland or X11?
Comment 2 Aaron Kelley 2023-05-24 23:15:57 UTC 
It is X11.
Comment 3 Nate Graham 2023-05-26 14:28:15 UTC 
Are you by any chance using the PLASMA_USE_QT_SCALING=1 environment variable? If so, this is Bug 423390.
Comment 4 Aaron Kelley 2023-05-26 19:32:20 UTC 
I set scaling to 200% through Settings → Display and Monitor → Display Configuration → Global scale.  It does not look like the PLASMA_USE_QT_SCALING environment variable is set to anything ("echo $PLASMA_USE_QT_SCALING" returns nothing) and I definitely never explicitly set it.
Comment 5 Aaron Kelley 2023-05-26 19:36:22 UTC 
Poking around a bit more.

If I take the bottom panel out of autohide, I get a one-pixel space ABOVE the panel and BELOW the maximized window.
If I move the panel to the right side of the screen, there is no space between a maximized window and the panel but there is still a one-pixel space at the bottom of the screen that the maximized window does not cover.
Comment 6 Nate Graham 2023-06-02 20:32:17 UTC 
Does the issue still happen...

...on Wayland?

...if you make your panel always visible?

...if you add `export PLASMA_USE_QT_SCALING=1` to the `~/.config/plasma-workspace/env/envs.sh` file (creating it if it doesn't exist) and then reboot?
Comment 7 Aaron Kelley 2023-06-10 13:40:13 UTC 
> ...on Wayland?
On Wayland it seems to maximize and properly cover the entire screen.

> ...if you make your panel always visible?
If the panel is always visible (and on the bottom), I get a one-pixel space between the top of the panel and the bottom of a maximized window.

> ...if you add `export PLASMA_USE_QT_SCALING=1` to the `~/.config/plasma-workspace/env/envs.sh` file (creating it if it doesn't exist) and then reboot?
This didn't seem to make any difference, I can still see the issue.
Comment 8 Nate Graham 2023-06-13 21:14:24 UTC 
Thanks for the info.

*** This bug has been marked as a duplicate of bug 414522 ***