Created attachment 150706 [details]
Tooltips artifacting and flickering (flipping enabled)

SUMMARY
On X11, with nvidia hardware, when quickly moving the mouse across icons in the task manager, frequently, an artifact of one of the preview tooltips will be left behind. As far as I can tell, with "Allow Flipping" enabled in nvidia-settings, the resulting artifacts will flicker (to be clear, this issue is present outside of the recording, so that option is not interfering with the recording). With "Allow Flipping" disabled, they are static. 

I was unable to replicate this bug when cycling through icons that did not have a window preview in their tooltip (i.e. applications that aren't open). It primarily seems to occur when transitioning from a tooltip with a window preview (particularly large tooltips displaying multiple window previews) to one without. I haven't tested to see if this issue is present on non-nvidia hardware.

STEPS TO REPRODUCE
1. Open some applications on the task manager
2. Quickly move the mouse between icons on the task manager

OBSERVED RESULT
Artifacts of the tooltips are left behind, and will flicker with flipping enabled.

EXPECTED RESULT
There should be no artifacts of the tooltips.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux 5.18.12-zen1-1-zen, Plasma 5.25.3
KDE Plasma Version: 5.25.3
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5

ADDITIONAL INFORMATION
Nvidia driver version: 515.57