The address bar (aka navagation bar) and the tabs above it could be good to 'auto-retreat' as opposed to F11 Fullscreen mode. Mouse to top of screen could retrieve them and a 'Pin' button to retain them located somewhere on the address bar.
Background to this: Windows already has the disappearing 'Start bar' at the bottom, activated by the windows key and mouse-down. Android smartphones have browsers with features to let the upper bars be consumed in scrolling and retrieved in back-scrolling.
I, and everyone else is losing an inch of screen space + the distraction of all the unnecessary tabs and buttons; F11 full screen is disorientating and requires concentration + the windows bar won't arrive with mouse-down and the sidebar is consumed giving only webpage, as indeed is the upper bars with no retrieval other than to 'flash' out of F11 fullscreen, again disorientating.
I think this is a necessary improvement to Windows and perhaps Windows code is the restriction here?