title: WS_EX_LAYERED window does not receive mouse events
body: <p>I'm coding a custom background non rectangular window with buttons such as minimize and close in bitmaps.
  <a href="http://pastie.org/1092728" rel="nofollow noreferrer">Here is my code just for now</a>
  The problem is the custom window does not receive mouse messages while hovering over non zero alpha regions.</p>