When I try entity snap to perpendicular in ortho mode it always gives me a point that is not on the target line - either before or after the line (still perpendicular). The offset from the target line is random - it is not a certain number of drawing units and when ortho is switched off esnap to perpendicular works fine. Maybe there is an internal variable that commands this offset, or some other setting that I am missing.

How can I set this offset to zero in ortho mode, so that when I use perpendicular esnap the new line ends up on the target line? 

PS. I am using the latest release of DraftSight on Windows 8 (64 bit)