Hi Günter, I can reproduce the issue with Dolphin. The window placement after a Plasma session restore works for me for other applications such as Kate or Gwenview though. Those windows are placed exactly where they were before the shutdown. But sadly not for Dolphin.
You can try to adjust how windows are placed on your desktop. The setting can be found in the System settings > Window Management > Window Behaviour > Advanced. If that doesn't help, then I suggest you either file a bug upstream or ask for help on either the forums (https://forum.kde.org) or on IRC/ Matrix. -- Med vänliga hälsningar Patrick Franz
