title: listbox selectionmode = multiextended how to get rid of selecting items with mousekey down
body: <p>When Setting the listbox selectionmode to multiextended I observed three ways to select items:</p>
  
  <ol>
  <li>pressing mouse key while holding shift key</li>
  <li>pressing mouse key while holding ctrl key</li>
  <li>pressing mouse key while moving mouse over unselected item</li>
  </ol>
  
  <p>1 and 2. is exactly the behaviour I want but I dont' want 3.
  because later I want to rearrange items by moving all selected items up and down with the mouse.</p>
  
  <p>How to get rid of 3. ?</p>
  
  <p>I need a behaviour just like the playlist in Winamp. Rearrange items by dragging and copy paste items</p>