Just to be sure I understand correctly, the screen locks up when you change the value on the numeric and then try to change the page on the tab, or does the tab have nothing to do with it?
In any case, does this happen only after changing the numeric? Does it happen if you change the numeric and do something else before changing the page? Does it happen when switching to every page? If not, what is on that specific page? As was said, an example would be very helpful (the smaller, the better).
Like I said, if this is caused by an event locking the screen, you should still have free access to your BD (place probes, open subVIs, open other VIs). Just open it before you run the VI. You can try canceling all the locks in the event structure to make sure it's not caused by this. Also, once it stops, you can try turning highlight execution on to see where it is.
Of course, testing it on a faster computer wouldn't hurt and should also be tried.
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