icon to reveal the “Quick Settings” sidebar.
The Quick Settings side bar can be invoked in two ways:
In Frameless Mode, there is no Toolbar or Settings button. This can make it hard to get out of Frameless Mode.
So there’ a Settings button, which ONLY shows up when you’re scrolling upwards really quickly. It goes away when you scroll up or down, and doesn’t appear unless you’re scrolling upwards really, REALLY, fast!
To dismiss it, simply scroll up or down.