ORYX Designer - a sequence flow without start/end point didn't saved.

1- put a sequence flow and a task in canvas 2- 1- connect start point of sequence to the task 2- connect end point of sequence to the task 3- don't connect sequence flow to the task and let sequence to be free 3-now save the diagram in this scenario ( at least one of start or end point of sequence is free) diagram save button doesn't work.