Bug 505910

SUMMARY
When using multiple desktops and multiple activities, when switching from one activity (e.g., X) to another (Y), if the selected desktop (e.g., 1) of the origin activity (X) is the same of the destination activity (Y) the behavior is correct. If, instead, the desktop that was previously selected in the destination activity (e.g., 2) is different from the one (e.g., 1) of the origin activity, then things get messed up. The first application  shown in the origin activity and desktop (e.g., X-1) are shown also in the destination activity and desktop (e.g., Y-2), and this application is shown over the other applications of the destination activity/desktop. The only way to  workaround the problem is to be sure to be in the same desktop  number in both activities before switching from one activity to the other. This workaround is also the only way of fixing the problem when it happens (i.e., you switch activity while they are set in different desktops).

This behavior has been around for awhile, probably since release 6 was introduced but, my bad, I haven't had time to investigate and report it before today.

STEPS TO REPRODUCE
1. Set up more than one activity and multiple desktops (3 activities and 4 desktops in my case). For simplicity, let's call the activities X, Y, and Z. Desktops are named 1, 2, 3, 4
2. In activity X, select desktop 2 and open an application
3. Switch to activity Y

OBSERVED RESULT
The application that is open in activity X, desktop 2 is shown in activity Y.

EXPECTED RESULT
Applications belonging to one activity are not shown in other activities.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.0
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.14.11-300.fc42.x86_64 (64-bit)
Graphics Platform: X11

ADDITIONAL INFORMATION