SUMMARY

When invoking the "end process" function in tree mode, the system monitor wants to kill a different process from the selected one.

STEPS TO REPRODUCE
1. Open system monitor (process page)
2. Ensure tree mode is active
3. Select a process and try to kill it (with Del key, context menu or End Process button)

OBSERVED RESULT

System monitor displays a dialog which shows it wants to kill a different process (usually systemd or kthreadd). When confirming this window, it actually attempts to send SIGTERM to the wrong process (which obviously fails).

Sometimes, it does not display a process name, and displays "PID %1, User %2". No SIGTERM is sent in that case. I believe this is a symptom of the same underlying issue.

EXPECTED RESULT

System monitor displays the correct process in the confirmation dialog, and SIGTERM goes to the intended process.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.22.0
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION

The kill functionality seems to work fine in list mode. The bug also happens on git master.