Created attachment 114402 [details]
Screenshots demonstrating the glitch.

NOTE: The actual package version is 5.13.4.

Overview:

When a process is running in the foreground, its entry in ksysguard consists of an icon and a name.

When a process is hidden but still running in the background, e.g. by being minimized in the tray, the icon is hidden in the ksysguard entry, leaving only the process name.

The space normally occupied by the icon when it's visible is not removed when the icon is hidden; instead all entries have some space to their left reserved specifically for their icon, presumably so they can maintain their alignment with the rest of the entries regardless of whether they themselves currently have an icon visible or not. This works as intended in default mode.

In tree mode, though, that approach actually produces a couple of visual glitches.

Steps to reproduce:

1) Switch ksysguard from "All Processes" mode to "All Processes, Tree" mode.

2) Have some apps running in the background. In my test case these will be nextcloud, polkit-kde-authentication-agent-1 and pamac-updater (not visible at first). I have also tested with qbittorrent, qsyncthingtray, yakuake, dolphin... It's pretty much a standard behaviour. [see first screenshot]

3) Open those apps in the foreground. In my case I restored nextcloud from the tray and at the same time ran pamac-updater and opted to refresh its databases, which prompted me for my password and brought polkit-kde-authentication-agent-1 to the foreground.

Icons for the apps appear next to their respective entries. The problem is that, because the space normally occupied by the icon is in this mode occupied by the tree hierarchy, the entry is pushed to the right so that extra space can be made for the now visible icon. This has the effect of actually BREAKING alignment. [see second screenshot]

4) Close the apps. In my case I minimized nextcloud to the system tray again, and at the same time entered my password in the prompt, ran the database update and closed pamac-updater.

What happens is that the icons disappear again, as expected, but here is the second, real glitch: the now text-only entries never go back to their original position, instead retaining the space previously occupied by the icon as empty padding. [see third screenshot]

This glitch can easily be "fixed" by closing and reopening ksysguard's UI. Switching tabs or modes doesn't have any effect though.

Also, this happens to every single process entry, but in the case of apps like e.g. dolphin it's not apparent because the entry is removed completely when the app closes (i.e. no background process) so the glitch is not visible for more than a split second.

Expected results:

1) Regarding the push-to-the-right issue, I don't know if something different can or should be expected. It could be ignored as a harmless tree-mode quirk, or it could be made so that the tree hierarchy occupies its own space instead of the icon space.

2) Regarding the second glitch, the behaviour should be that at least the entry returns to its original position after being pushed to the right. In other words, the extra space for the now hidden icon should be removed.