I just updated my lumia 535 to windows 10 mobiel build 10586 yesterday. One thing i noticed is that there is no option or menus regarding on screen button. dont get me wrong, i dont hate them, but windows phone 8.1 give me options to swipe up or tap at the left side to hide them. Now for win10m, i still can swipe up to hide, but when some apps were opened it wont respond to hide. for example UC browser.
You mean navigation bar? For some reasons you cannot hide it when using WM 8.1 apps, only works for WM10/UWP apps.