panel locks after upgrade to F25

[Maurizio Marini]

Hello
after upgrade to F25, panel locks randomly.
I have KDE and plasma5.
When it happens CTRL+ALT+F2 and back CTRL+ALT+F1 works for me.
I wonder if I can clear something inside .config, something that is recreated
fresh after logoff and login, to fix the issue
or should I ask on ked mlists?
Many thanx in advance
-m