Currently the context palette only support drag and drop.  However when the user simply clicks on the button it will act as a drag and drop with no 
movement.  Therefore a new node and edge are created.  The problem is that the new node is on top of the original node.  

A better behavior would be to add special logic to the click action to create the new node a set distance from the original node.  It may still cover another 
node, but that would be better than the current situation.  Also some of the buttons could have special logic.  For example a message to self could be created 
by simply clicking on the message context palette button instead of dragging back to the original node.