title: MouseLeave not firing if a WinForm has only one full-docked ListBox
body: <p>I have a Form with only a simple listbox. The listbox is Full-docked and the Form's FormBorderStyle is set to None.</p>
  
  <p>When I attach a MouseLeave event to a form, it does not fire. (It also does not fire MouseMove, MouseHover etc.)</p>
  
  <p>However, if I undock the listbox and resize it so at least a part of the form is visible and if I move mouse over the visible part of the form, all mouse events fire again.</p>
  
  <p>How to get the form to receive mouse events even if it's consisted only of a full-docked listbox?</p>
  
  <p>Thanks</p>