Created attachment 138546 [details]
picture of problem: KDEPlasmaBug.png

SUMMARY
When opening multiple windows of firefox and they are put together on the program banner they do not report correctly as miniatures.
e.g. the attached picture shows the problem
If you have 3 different webpages open on the 3 different windows of firefox open they show as they would be on the same page.
firefox 88.0.1 (64-bit)
@KDE-neon
KDE plasma version 5.21.5
KDE framework 5.82.0
kernel 5.4.0-74 low latency
64 bit graphics: X11
STEPS TO REPRODUCE
1. open multiple windows of firefox
2. let one window play a youtube clip, and paus it
3. let the other windows show other web pages.
4. notice that the miniatures show all the same.

OBSERVED RESULT

notice that the miniatures show all the same.
EXPECTED RESULT

to show miniatures of each window as with other programs.
SOFTWARE/OS VERSIONS


Linux:KDE-neon
KDE plasma version 5.21.5
KDE framework 5.82.0
Qt Version: 5.15.2
kernel 5.4.0-74 low latency
64 bit graphics: X11
ADDITIONAL INFORMATION