title: Highlight a possible drop target while dragging a shape/group in KineticJS
body: <p>I am using KineticJS for implementing a graphical editor. I would like to drag a KineticJS Group and drop it into another shape. So far so good, done binding the "dropend" event to a handler in the group.
  But I would like to change color to the potential destination shape while hovering on it during dragging, so as to give evidence that it is a suitable shape for drop.
  I can't see a way of doing it and I am not been able to find any help in Kinetic documentation. How could I do?</p>
  
  <p>Thanks,
  eca</p>