ExpPanel signals updates length change in callback

[k1o0]

The following error is raised in expUpdate:

Warning: Error occurred while executing the listener callback for event ExpUpdate defined for class srv.StimulusControl: In an assignment A(:) = B, the number of elements in A and B must be the same.

Currently caught and put into more informative warning, e.g.

Warning: Error caught in signals updates: length of updates = 24, length newNUpdates = 55

Since increasing the time between updates the mismatch number has increased to roughly half. Perhaps the expUpdate function is being called before the previous call has finished executing? If that possible?

[k1o0]

Duplicate of #59