title: How to register a user event defined in a SUB VI(LabVIEW)
body: <p>I created a SUB VI and defined a user event in it.
  Then I created another VI, let's call it MAIN VI.
  I put a SUB VI in the MAIN VI,and I want to register the user event created in the SUB VI to the Event Case in the MAIN VI, what should I do?</p>