I have created my Group Drawing, everything is Positioned and Marked.
If the elements have no 3D information anymore (only 2D lines used in detail style) you need to use 2D Position flags. It needs to be a Group existing to get a Group part list.
Best regards
Bentley Structural YouTube Channel
Bentley Technical Support
Johannes Michalowsky
User Success Support - Bentley Systems
ServiceRequest Manager
Thank you Johannes, I deselected "As true 2D Lines" in the Edit Styles-> Common->Display dialog. And my "Drawing Parts List" now works like a charm.