Function route 

pub fn route(event: &BrowserInputEvent, tab: u16) -> Route

The route one event takes, into the tab whose page the viewer is on.

A pointer gesture belongs to the host, a keystroke to the page. CEF routes its own mouse calls into a windowless popup - a select’s menu is its own view - and a click sent to the page target instead reaches only the page’s widget, so the menu treats it as an outside click and closes.