Hey,
I want to suggest two things:
1.) Don't override start() but start(Type) in SimpleApplication, well, I would even say, in all subclasses of Application.
so 2.) Make the start() method final, so things like this don't happen.
The problem is, when you call e.g. app.start(Type.Graphical), you still want to see the Settings Dialog. And I think you should disable it manually, if you don't want to let it show in Canvas mode for example.
Just my 2 cents…
Cheers,
Tim