I've had this issue with BTB on all three computers I've run it on. When I click and drag to place a node/drag a control arm/whatever, nothing changes on screen until I release the mouse button. The first time I encountered this issue was on an XP 32bit machine several years ago, and it only started after I had placed an image as the background to trace my track map. After I did that, this issue started on that computer and never went away. Since then I've tried it on two other computers (both running Win7 64bit, as an administrator) and they both suffer from the same problem. It's caused me to not use the program pretty much at all, since I can't see what I'm doing while I'm doing it. All computers I've tried it on were, at the time of trying, fairly quick. The latest machine is a Lenovo mobile workstation that I've had for maybe 6 months or so; it was about $2300 and was built for the purpose of running intensive programs like Solidworks. It's a quick machine, so it's not a raw power issue. I have DirectX 11 installed on it (though there might be an update that I could download). Now, I've had this issue on all three computers I've tried it on - so any ideas what is going on? Is there some windows setting somewhere that deals with performance of 3D stuff in windowed programs or something? I'd really, really like to use this awesome tool to its fullest.