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.