title: how to determine which event calls procedure in delphi
body: <p>I have a procedure named XYZ(sender:TObject) in delphi. There is one button on my form. </p>
  
  <pre><code>Button.onclick:= xyz;
  Button.OnExit:= xyz;
  </code></pre>
  
  <p>Both the events calls the same procedure. I want to determine in procedure XYZ, which event calls this(onclick or onexit) and according to that proceed with coding. 
  How to determine which event gets fired? thanks </p>