UndoOff prevents HExtrude from working?

[scfabian]

After a lot of trying I found out that the UndoOff-Procedure prevents HExtrude from working in VW11!

The following code should produce a polygon and extrude it, but the extrusion doesn't happen:

code:

---

PROCEDURE testExtrude;

VAR

h: HANDLE;

BEGIN

UndoOff;

ClosePoly;

BeginPoly;

AddPoint(0,0);

AddPoint(2,0);

AddPoint(2,2);

AddPoint(0,2);

EndPoly;

h := HExtrude(LNewObj, 0, 4);

END;

[/code]

If I take away the UndoOff, everything works fine. Is this a bug or a feature? At least I found no hints in the documentaton and now I wonder if there are more nasty side effects of the UndoOff procedure. Anyone with similar experience?

Fabian