title: Disabled menu items in Winforms still show subitems
body: <p>If I create a menu with two items (say "Item1" and "Item2" and then create two subitems under each one (1A, 1B, 2A and 2B), and then disable Item1, I'd expect that 1A and 1B wouldn't show.</p>
  
  <p>And, indeed, if I move onto Item1 they don't.  Unless I then move on to Item2, wait for 2A and 2B to show, and then move back to Item1.  At which point 1A and 1B both pop up, fully active.</p>
  
  <p>Is this a known bug?  Is it something I can work around?  Any suggestions?</p>
  
  <p>The users want to be able to see the things that are currently disabled, or I'd just make things invisible.  Sadly, this isn't an option we can easily use.</p>