Salutations,
I've written a little vi that should do something along the lines you are talking about. If this VI doesn't help you, then please tell me what's wrong with it, and I'll try again.
It's an event structure that gets information when you hit "okay" and will stop the vi when you hit "stop". However, everytime the mouse button goes down, it updates the range for each of the graphs. Now, this will work when you hit the scrollbar, but also if you hit something else, it should update. This might not be the most efficient way of doing things, but this is how I've done it in the past.
If you have any questions, don't hesitate to ask. I didn't take the time to write it all out, I hope it makes sense. I've also turned off auto-scaling in the graphs. I've only done the updating for the x-axis as well, I'm sure you can apply it to the Y if necessary.
Sincerely,
ElSmitho