Fired after finishing dragging shapes or connection.
A value indicating which handle of the connection was dragged. The value will be
"source" for the source handle,
"target" for the target handle and
undefined if the entire connection was dragged.
An array with the dragged connection.
An array with the dragged shapes.
The widget instance which fired the event.
A function that can be used prevent the default action. If invoked, the dragged elements will be returned to their original state.