Add a smooth page adoption in a Full Screen view, while hovering a top-bar on MacOS

performance
#1

while using a full screen view on brave and pointing the mouse arrow to the top screen area, it show a general menu ( system wide) options on mac, just exactly as it should do. However, this system top menu slides down and changes the position, where the Brave browser tab section, and the web-page begin, from top to down. And when it happens, the page unpleasantly drugs.
The example is here https://bit.ly/2BWwUeM

I would just like it to be smooth, like Safari does (show in the example video)