I have a model with several sketches that ultimately control some geometry wwwaaayyy down stream.  And I want to change several of the dimensions in the sketches and then rebuild. (so I don't have to wait each time I change a dim.)  It seems that most of the time, I change a dimension and the model automatically rebuilds.  Some times I change a value and the system waits for a CTRL-B or Q.  Is there any logic around when it waits for my instruction and when it goes off on its own?  Is there a way to force it to wait until I say "go"?

-Nate