Workflow editor wrong drawing when adding a task

See the StudioWorkflowWrongDrawing.mp4 attachment. Basically:

• Add a task, like Accept/Reject
• Move a transition from another task to the input of the new task

Bugs:

• No drawing of transitions during the drag and drop
• No refresh after droping the transition to the new task
• When clicking the task to force the refresh:
• We lost an output transition from the source task