Can't get full screen on 6s – midiSequencer Review

There are 3 screen size choices, none of which fills the whole app in the screen on a 6s. Buttons are extremely tiny which makes it difficult to use. This should have been for iPad only, I can't see using it at all always toggling screens where you either get a half screen of the full app(look at the picture), the top part, or the bottom. I may have well tossed my money out the window. I rarely give negative reviews, but this is ridiculous.
Review by Fgyjgfdhccfv on midiSequencer.