Win7pro 32bit Wininstaller Qcadpro 3.23.0

Draw an arc.
Select the arc.
In Property Editor:
Set start angle to 135
Set end angle to 135

SweepAngle = */-360

edit the end angle and add "+360", hit enter

SweepAngle = 0

An arc with zero sweep is a point.
A point is not an arc.
With the same start and end parameter an arc should have a sweep of +/-360.
As for entries by points or by angles.

Regards