Hello Attila!Hi lulukom,
I just tried the AU plug-in from v4.7.2 and v4.8b6, both worked well with DP 11 (11.22.93087).
Closing and reopening the window worked, as well as resizing the window.
The only small issue is that you can move the window only by dragging the window top area, below the title bar (title bar dragging does not work for some reason).
Which DP version do you use?
Right now I'm using DP 11.22. I have two old Macs now. Both feature Os High Sierra. Doesn't work on both AU. Maybe it's too old Mac?) But almost all programs and in particular music work well and without problems. I also want to say that your other programs (Syne, Midi Mutator, etc.) as plugins have the same problems for me in DP. I do not know why it is so ? RC v4.8b6. If you are interested I could make a short video again.. And yes, two windows open - one is empty and can be dragged, the second is normal, but it does not respond to either dragging or control ((.