There is the possibility that you can limit the screen size of an app (width, height).
I haven't figured out how to make a page invisible. The attribute Page.visible = .f. I couldn't find anywhere. The same problem have you have with the section, also here has were try section not visible to put, resp. only if certain requirements are met. It would also be enough for me if the section could be folded in and only unfolded if a condition is met.