title: What would be the expected behavior for a window that hides itself upon keystroke
body: <p>This is a subjective question, but I need opinions.</p>
  
  <p>I have a WinForms C# application whose window hides itself after a specific keystroke (Enter or Escape), with possible modifiers (e.g. Ctrl-Enter). When hiding on KeyDown or KeyPress, the other application that becomes active after my window hides itself receives the KeyUp event for that keystroke. Normally, it shouldn't affect that other application, but some of them out there react on KeyUp. For example, TweetDeck sends the message currently being edited on "Enter" KeyUp, even if it did not receive KeyDown/KeyPress.</p>
  
  <p>So I thought, fine, I'll be a good citizen, I'll hide on KeyUp. But this doesn't feel right. If I only look for keys up, I'm doing what I blame others of doing! If I try to create an history of matching KeyDown/KeyUp, I'm over-complicating my code (modifiers generate their own key up).</p>
  
  <p>What should I do? What should a well-implemented application do?</p>