Improve Auto Transition Listener so that fields are not nulled out

Using the Auto Transition Listener, one can run an existing transition. In my case the transition I wanted to use had the "summary" field on it. When the Auto Transition Listener runs, it sets the "summary" field to null.

I have noticed in the APIs that run transitions, those APIs state that any field not specifically set in the transition are set to null. However there are function calls (getFieldsForAction, for example) that help this design decision.

I would like to see the Auto Transition Listener to use some function like this so that I don't have to have a special transition for the Auto Transition Listener.