@Jef!:
I think you understand the difference between vla-put-activeviewport (for MS "VPORT") and vla-put-activepviewport (for PS "VIEWPORT") now. It is indeed a bit confusing (and in your last post you still mix things up a bit).
Of course faulty information in the documentation does not help...
"The ActiveSpace property (equivalent to the TILEMODE system variable) determines the type of viewport used."
http://help.autodesk.com/view/OARX/2018/ENU/?guid=GUID-2B609059-6B70-4C66-A442-F5917363462A
A "VIEWPORT" gets activated despite the error message, because this occurs before the call to vla-put-activeviewport:
Ok, I get it now. So I never "controlled" which viewport got activated, I just changed the The ActiveSpace property and happened to have only 1 viewport. Thanks a lot for taking the time to shed light!
Faulty information in the documentation indeed does not help... have you seen the following sentence of the one you quoted from the page you linked? "No editing or view changes can be performed unless the viewport is active. To make a viewport active, use the ActiveViewport property on the Document object" (!).
If I understood correctly this should be "No editing or view changes can be performed unless the viewport is active. To make a viewport active, use the ActivePViewport property on the Document object"... right?
