There were several problems.
Since you read the value of the Stop SubVI button at the beginning of the sub vi you won't get this to stop unless stop subvi is pressed before you start the subvi.
Since the subvi won't exit now, the event structure will not complete. In fact, if you look at the event structure's properties, you will see that the panel is "locked" while you wait on this event to finish. This means the LabVIEW will not process any more events until the structure completes. Since it never will, you will not recieve any other mouse clicks.
Speaking of the subvi not completing, it is generally not a good idea to call a subvi synchronously that runs indefinately inside the event structure. Instead, you should call the VI by invoke no
de and not wait for it to complete.
I have included a set of changes that I think makes the VI run a little better. A text file lists my changes, and the llb has the modified VI's. This is only one solution to this problem, and there might be better ways.
