Produce warning when changing engine type in data function

Users can change the engine type in a data function without resetting all of the code, inputs, and outputs, which is fantastic.

However it is maybe a little too easy to change this.   I found just an accidental touch of the mouse scrolling switched the engine type (from TERR to OSR) and I just happened to notice.    Since this could create unexpected behavior it seems that a pop-up or something would be appropriate to ask the user if they really meant to switch the engine.   Changing e.g. from TERR to OSR would not really be immediately apparent but there may be some differences that would be hard to track down if you didn't realize the engine had been changed.