Bug 469856

Summary: Random different gaps between "icon only task manager" and preview popup on mouse hover
Product: [Plasma] plasmashell Reporter: postix <postix>
Component: Task Manager and Icons-Only Task ManagerAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal CC: nate, niccolo.venerandi
Priority: NOR    
Version: 5.27.5   
Target Milestone: 1.0   
Platform: openSUSE   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Screen recording

Description postix 2023-05-16 15:14:51 UTC
Created attachment 159002 [details]
Screen recording

STEPS TO REPRODUCE
1. Use the icon only task manager, panel size 34, scaling 200%
2. Have two applications, e. g. OBS Studio and System Settings running
3. Hover the mouse over one of the icons in the task manager
4. Move the mouse the other icon
5. Repeat with step 3 one time again
6. Finally from step 5. move the cursor upwards to the desktop
7. Hover over the icon again from where you just came

Or just watch the screen recording. :)

OBSERVED RESULT
There randomly gaps between the preview and the panel: 
* No gap
* Roughly 50% of the panel height
* Roughly the height of the panel

EXPECTED RESULT
* No gap

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20230514
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.9
Kernel Version: 6.3.1-2-default (64-bit)
Graphics Platform: Wayland
Scaling: 200%
Comment 1 postix 2023-05-16 15:31:10 UTC
I believe this has something to do with the third application I had running and which can be seen in the screen recording: Firefox, which was playing some media and thus its previews shows controls.

Testing a little bit more, it looks like what is displayed in the preview and how it is displayed (size, position) is racy and depends on the other apps in the icon-only taskmanager.
(E.g. when moving the mouse from one icon to the other, sometimes the previews doesn't change but shows the former hovered app.=
Comment 2 postix 2023-05-16 15:49:22 UTC
Sometimes the lower edge of the  (Firefox) preview with the media control buttons is also displayed on the bottom of the panel.
Comment 3 Nate Graham 2023-05-16 19:24:19 UTC

*** This bug has been marked as a duplicate of bug 463272 ***