Offset for objects and polylines

Hi, All!
Hi, Dongxu Li ;)

"Modify, Offset" will be very useful function for prepare files for laser cut.
But now it is not working. Also not working "Polylines, Equidistant" (did not connect start and end point in result)
May be need help in testing or in coding?

Using "Polylines, Equidistant":
Original polyline are open? result polyline are open
Original polyline are closed? result polyline are closed

Note:
A polyline is closed if the "closed flag" is set clicking in close button on draw
or in modify->properties

Oh, yes! (( Sorry for "Polylines, Equidistant", I really forgot close polyline.
And what about "Modify, Offset" will it work in 2.0 or will be disabled?