Bug 503128

Summary:	Visual bug on the second monitor after fullscreen exit of the QT app
Product:	[Plasma] kwin	Reporter:	konstantinmagin
Component:	multi-screen	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	minor	CC:	kdedev, nate
Priority:	NOR	Keywords:	multiscreen
Version First Reported In:	6.3.4
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description konstantinmagin 2025-04-21 17:08:35 UTC

SUMMARY
Visual bug on the second monitor after fullscreen exit of the QT app

STEPS TO REPRODUCE
1. Have connected 2 monitors
2. One first monitor enter into fullscreen on any QT-based app
3. Left fullscreen mode

OBSERVED RESULT
Visual bug on the second monitor after fullscreen exit. 
Video of the bug is posterd on the [youtube.com](https://www.youtube.com/watch?v=RWQu8QjiZw0) 

EXPECTED RESULT
No visual bug

SOFTWARE/OS VERSIONS
Linux: Nobara Linux 41 (Fedora 41) 
KDE Plasma Version: 6.4.3
KDE Frameworks Version: 6.13.0
Qt Version: 6.8.2

Comment 1 TraceyC 2025-04-21 22:41:38 UTC

Thanks for reporting this bug and for the screen recording. I can clearly see the visual glitch after you make About This System full screen and restore the window.

GPU: NVIDIA GeForce RTX 4070, Wayland session

Can you please run 'kscreen-doctor -o' and paste the output in a comment on this report? Thanks!

Comment 2 konstantinmagin 2025-04-22 16:04:46 UTC

No problem!
Output:
```bash
Output: 1 DP-2
        enabled
        connected
        priority 2
        DisplayPort
        Modes:  1:2560x1440@240*!  2:2560x1440@180  3:2560x1440@165  4:2560x1440@144  5:2560x1440@120  6:2560x1440@60  7:1920x1080@144  8:1920x1080@120  9:1920x1080@120  10:1920x1080@60  11:1920x1080@60  12:1920x1080@50  13:1920x1080@24  14:1280x1440@60  15:1680x1050@120  16:1680x1050@60  17:1600x900@60  18:1280x1024@75  19:1280x1024@60  20:1440x900@60  21:1152x864@75  22:1280x720@60  23:1280x720@50  24:1024x768@75  25:1024x768@70  26:1024x768@60  27:800x600@75  28:800x600@72  29:800x600@60  30:720x576@50  31:720x480@60  32:640x480@75  33:640x480@73  34:640x480@60  35:640x480@60 
        Geometry: 1707,0 1707x960
        Scale: 1.5
        Rotation: 1
        Overscan: 0
        Vrr: Automatic
        RgbRange: unknown
        HDR: disabled
        Wide Color Gamut: disabled
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer efficiency and performance
        Brightness control: supported, set to 100% and dimming to 100%
Output: 2 DP-3
        enabled
        connected
        priority 1
        DisplayPort
        Modes:  36:2560x1440@60!  37:3840x2160@60  38:2560x1440@240*  39:2560x1440@165  40:2560x1440@144  41:2560x1440@120  42:1920x1080@60  43:1920x1080@60  44:1680x1050@60  45:1600x900@60  46:1280x1024@75  47:1280x1024@60  48:1280x960@60  49:1152x864@75  50:1280x720@60  51:1280x720@60  52:1280x720@50  53:1024x768@75  54:1024x768@60  55:800x600@75  56:800x600@60  57:720x576@50  58:720x480@60  59:640x480@75  60:640x480@60  61:640x480@60 
        Geometry: 0,0 1707x960
        Scale: 1.5
        Rotation: 1
        Overscan: 0
        Vrr: Automatic
        RgbRange: unknown
        HDR: disabled
        Wide Color Gamut: disabled
        ICC profile: /home/smoke/Загрузки/sRGB-v4.icc
        Color profile source: sRGB
        Color power preference: prefer efficiency and performance
        Brightness control: supported, set to 100% and dimming to 100%
```

Comment 3 TraceyC 2025-04-22 18:09:53 UTC

Thanks for that. I'll let one of the more experienced kwin contributors take things from here