Thank You Michael,
that ist the solution. I wasn't aware that the OSX version is also the one for Windows.

By the way: I tested the DXF-Layers -> MIO Styles function in the new V4-Beta, it it works well in my tests until now. Thank you also for that feature.

Best Regards, Paul

PS: I found some problems in Boolean Difference with some Objects (they should do, but they don't), also there are some request for shells and offset-functions, as I am trying to construct the fuslage of my plane. I will do that in another forum-entry soon.