HTML5 fullscreen is an immersive experience with one window taking over the entire screen. window.focus() is a request to change the focused window, and thus is incompatible with the immersive experience of fullscreen.
In bug 776418 this incompatibility is exploited. Because they have different goals (immersion vs multi-window operation), this should not affect legitimate sites.
Comment 1 by avi@google.com
, Jan 8 2018Components: UI>Browser>FullScreen
Labels: -Pri-3 Pri-1
Owner: a...@chromium.org
Status: Started (was: Untriaged)