How to remove phone menus?

How do we remove menu or force full screen on smartphone ?

i test my game on nexus 5 and the widget are bad because there is this little phone menu on the bottom of the screen

when i test somes other apps this menu disapear, how can we remove this menu bar with ue4 in blueprint ?

Thanks

Dupe of : How do I hide on-screen buttons on android devices? - UI - Epic Developer Community Forums