Introjucer unresponsive for long periods

I have been working with both VS2010 and Introjucer at the same time, and I am finding I have to wait over a minute sometimes to get Introjucer to respond.  I'm sort of assuming it is looking at the source files (which will have changed) but is this normal behaviour.  In a system that is so good in so many ways, this seems a strange anomoly.

Yeah, there's something odd about the big-O behaviour of the TextDiff algorithm that makes it very slow under certain circumstances. (Very hard to know what could be done about it though)