How to get "out" of the full screen in applications on iPhone? I'm often using some news applications (like WP.PL) which sometimes enter in full screen mode on my iPhone. It means all the buttons dissapear and there's only text/photos to read. Swiping left/right switches between news but all I would like to do is to get out of the full screen and continue reading with ability to change categories etc.
I tried multiple options and 99% of times it gets out of full screen mode but it's more of a random pushing the glass (multiple times) than actually "knowing" how to leave full screen. 

Is there some sort of finger combination for all applications or is per app setting I have to leave with ?
It's a per app setting. but most app follow the standard settings.

try tapping once in the middle on the screen and see if the controls now show up.