title: How to disable MouseWheel if mouse is not over VirtualTreeView (TVirtualStringTree)
body: <p>TVirtualStringTree behaves by default if it is focused - it will scroll on mouse wheel even if mouse is not over control (except if it is over another TVirtualStringTree).</p>
  
  <p>Is there a quick and elegant way to disable this behaviour?</p>
  
  <p>I already did this with <code>OnMouseWheel</code> event and checking with <code>PtInRect</code> if <code>Mouse.CursorPos</code> if it is over a control but I have a feeling that there is a better way to do the same because this way I'd have to define a new event for each TreeView I add and also handle when to focus/unfocus the control so I hope there must be a better way to disable this.</p>
  
  <p>So to be clear, I want mousewheel function to work as usual, but only when mouse is over VirtualTreeView.</p>