title: How to detect context menu disappearance?
body: <p>I need to make a control with popping out menu and button that causes it to be displayed and has changed (pressed) appearance during the time popped out menu is visible.</p>
  
  <p>Currently i am using check box with Appearance property set to button and context menu. However detecting a moment when menu disappears from any reason other then click on one of its items (which generates Click event that can be handled) - for example, when the form is clicked - wasn't successful, as "Collapse" event didn't occur. As a result, "down-arrow button"  didn't change its appearance back as intended.</p>
  
  <p>How can disappearance of ContextMenu be detected? What are conditions for "Collapse" event to occur?</p>
  
  <p>P.S. On related note, i was trying to implement the same thing with listbox set as top level window before; when form was clicked, it changed appearance but the loss of focus didn't occur. Any help with detecting the moment when it occurs would be greatly appreciated.</p>