Hello @linux-aarhus ,
I never ever used Gnome and will never do 
In none of my posts I wrote that I have Gnome?
Since I use Linux.
I began with Suse, than OpenSuse and now Manjaro always I had KDE.
Here in my 1. Post I started, I copied my System Info.
Even in the other My System Info
Sorry No Idea how and why you came on gnome 
Yes I replaced pamac-gtk3 with pamac-gtk (gtk4) and now the authentication dialog works as expected?
As of now.
Exactly the “screenshot” windows
It was gone and not hidden behind.
But now after replacing gtk Version it not happens anymore.
In KDE as of now and It seem to be solved.
Wish you well
Tony