Unfortunately the problem persists in DS 2016. If, while in paper space, you activate a model space viewport, the lag returns worse than ever... even after you deactivate the viewport.
Starting DraftSight with the mouse unplugged fixes the problem but the mouse wheel doesn't work after plugging it back in. There is a bit of a work-around for this if you have two mice...
[ol 1]
Start DraftSight with one mouse plugged in and the other unplugged
Plug in the second mouse after...