When I add subtasks, the subtask area does not grow with new added tasks, see this short video in action:
http://www.screencast.com/t/Rdj3EJLvhV5L
I think it's related to upgrade to Mac OSX 10.11.
Thank you so much for making a video for us, we will try to fix it soon in our next version.
Recently the update may be a little bit slow, and later we will keep improving Doit.
Thank you for your feedback and support.