The "quick peek" feature in full screen mode is useful: when hovering the mouse on the top edge of screen in full screen mode, tab bar and address bar will pop up to allow you to change tabs, enter new address, interact with extensions, etc.
However, the transition of the popped-up bars is extremely unnatural. The entire webpage move down without any animation to clear some space for top bars. And it will suddenly move up when you exit top-hovering. Forcing users to watch the webpage jumping back and forth simply because they what to peek the bars is not a very good idea. Actually, please do not change how the webpage is displayed unless the user intended to do so.
A better way of handling this is to keep the webpage still and display the top bars over the web content when hovering, ether with transition animation or not. Of course, the scroll bar still needs to be shortened and updated.
I believe this modification can greatly improve the user experience in full screen mode. Hope we can see this in future updates.