Possible weirdness with Dim Pro and Session Drummer

ok, it's been awhile since I've got to play with Dim Pro and Session drummer-but I'm noticing some strangeness with both...when changing a value using my mouse the knobs and such do not move with the mouse movment, once I release the mouse the knobs will snap to the new location. This is only happening with Dim Pro and Session Drummer. Rapture and all other synths seem to be fine...I can't remember if this is normal behaviour or not. Anybody else notice this..? BTW I'm using Sonar Pro 7, on a Intel Core 2 Quad system with 4 Gig of ram and a Nvida PureVideo graphics card...