title: How to find what caused an event? VB.Net
body: <p>I have a Handler for a ComboBox.SelectedIndexChanged event. The 'sender' tells me that it is the ComboBox that caused the event, and what its text and value currently is, but what I need to find out is what caused the ComboBox to change its selection in the first place?</p>
  
  <p>How do I find out which line in my program is causing the ComboBox to change, please?</p>