Jirk,
The first time I reopen it, it has move 1/2 toward the bottom. The second time is is back at the bottom.
If I move, close, quits PM+, reopen PM+, the open the dialog, it has moved 1/3 down. Close the dialog and reopen, it is then another 1/3 down, close and reopen again and it is back at the bottom.
I'll play with some other dialogs to see if they do the same, but the Copy/Move is the only one I have noticed so far.