title: JGraph - overriding cell drag
body: <p>This is quite a long shot, I know it's a question about a very specific package.</p>
  
  <p>I'm trying to stop nodes from dragging into a certain area of the graph.</p>
  
  <p>I have written code to detect when the mouse is dragged over a node,  however it is a bit of a hack. I am trying to get the node that the mouse is dragging and its XY co-ordinates but have no idea how to do it.</p>
  
  <p>I can't find any methods to override this, the marquee handler doesn't get called for a node drag. I'm looking at overriding the BasicUI class, but don't know</p>