Drag.dropDone

Informs GDK that the drop ended.

Passing false for success may trigger a drag cancellation animation.

This function is called by the drag source, and should be the last call before dropping the reference to the drag.

The gdk.drag.Drag will only take the first gdk.drag.Drag.dropDone call as effective, if this function is called multiple times, all subsequent calls will be ignored.