>Anyway. try to scan the process with Process Monitor. It shows all access - one of it it must be. Ah, and let us know ...

Good Idea!!!
Et voila:
Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
Browse For Folder Height
Browse For Folder Width

These are the width and Height values of the getdir(,,,64) Dialog.

Thank you for your hint!
Now I hope to Solve my customers Problem...

CU