Bug 490119

Summary: With fractional scaling, grabbing to resize a panel element's dropdown menu causes it to jump when grabbed and jump slightly when it is resized
Product: [Plasma] plasmashell Reporter: Eamonn Rea <eamonnrea>
Component: PanelAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal CC: akselmo, nate, niccolo.venerandi
Priority: NOR    
Version: 6.1.2   
Target Milestone: 1.0   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Eamonn Rea 2024-07-11 16:22:39 UTC
SUMMARY
With at least some fractional scale factors (such as 145%), when you click on a panel element (such as network settings, etc) to show its dropdown menu, grabbing to resize the panel will cause it to jump very slightly. In my case with a panel at the top of the screen, with a panel element to the right of the panel, the dropdown menu jumps slightly to the left.

When moving on to resize the panel, it will jump a very small amount as well.

This is differeent to what is experienced when resizing quickly and having the *contents* jump around while it adjusts to the new size, this is about the dropdown itself jumping around a pixel or two. 

I mention fractional scaling because I am aware there have been, I believe, some rounding issues that cause this sort of behaviour (such as Bug 489016).  

STEPS TO REPRODUCE
1. Have a fractional scale factor (unsure at time of writing if it is required for reproducing the problem)
2. Open a panel element's dropdown menu (such as network settings)
3. Click to begin resizing the dropdown
4. When "grabbed" after being clicked, the dropdown itself will shift very slightly in some direction; for me, it is to the left, but this could vary depending on panel location and the location of the panel element.

OBSERVED RESULT
Panel element jumps very slightly when being grabbed. It continues to jump around after being resized.

EXPECTED RESULT
Panel content location should not jump like this.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.9.8 Linux Zen
KDE Plasma Version: 6.1.2
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
Extremely minor issue but could help iron out any fractional scaling rounding issues.
Comment 1 Akseli Lahtinen 2024-07-12 12:46:48 UTC
Can confirm, on scale factor 145% sometimes panels when resized jump a bit, however they have to be in center of the screen.

For example set panel full width of screen, then add two spacers. 
In middle of those spacers, add a digital clock.
Open digital clock and resize it. Sometimes it jumps around, but only at specific spots. 
Closing and reopening the applet does solve the issue though.

Operating System: Fedora Linux 40
KDE Plasma Version: 6.1.80
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2
Kernel Version: 6.9.7-200.fc40.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 6600
Comment 2 Akseli Lahtinen 2024-07-12 12:47:12 UTC
Interesting, I can make this happen with non-scaled display too.
Comment 3 Nate Graham 2024-07-19 14:48:51 UTC

*** This bug has been marked as a duplicate of bug 481829 ***