title: winforms detect change of focus within flowlayoutpanel
body: <p>I have a flowlayoutpanel, and I'm adding a user specifcied number of custom controls to it at runtime.  What I want to do is detect when the flowlayoutpanel's children lose or change focus.  </p>
  
  <p>So, in other words, how can I tell when one child control loses focus?  I need to be able to see this at the flowlayoutpanel's form, so I can do some calculations.</p>