Devuan Stretch, Plasma 5.8, KDE 5.28

In folder view when carrying out an action, e.g. Create New>Textfile or dragging a file to Wastebin the display of the confirmation dialog is inconsistent. Sometimes it's displayed normally but at other times it's minimised and has to be restored by clicking on its entry on the panel. Is this a bug or is it a configurable setting? Also could it be related to the fact that the panel, set to autohide, bobs into view as soon as the mouse is clicked on the desktop or any window and stays there until it's moused over? (I see the latter issue was raised some weeks ago without a reply.)

It's a configurable setting. Go to System Settings -> Window Management -> Window Behavior -> Focus, set 'Focus stealing prevention' to 'None'.

Thanks for that. The over-active panel problem seems to have been cured by switching to lightdm.

It seems neither problem has been cured. The panel unhiding is back and the minimised display of dialogs is erratic so that although some of the time they appear to be behaving and give the impression that the problem is fixed it isn't really.
Between them these two annoyances are making the system very unpleasant to use. Tomorrow's task is going to be to cut a live disk of Jessie to see if the hardware will support that and go back to KDE4 if I can. I've been a KDE user for a very long time and have never had problems like this before.

I think the two problems may be related. It will take extended experiment to check but it appears that if the panel isn't hidden dialogs are displayed normally. Whether it's one bug or two I'm not sure but if it's verified I'll file at least one bug report.