When I try typing with my Project Targets window open on a full size novel with a good 30+ documents and almost 50,000 words there’s lag in my typing (at least when typing in full screen mode; I don’t usually type in non full screen mode, so haven’t noticed). I’d prefer if the Project Targets only tried calculating word count on some period of inactivity, like the auto save, so that there’s not lag as I type and edit, but I can still leave Project Targets window open to get updated progress bars when I’d like. It’s important to some of us NaNo-ists. 