Comment 1 for bug 1508130

After a bit of investigation, I understand what’s going on: the Chrome instance is a focus scope that proxies focus requests to the address bar, and it’s itself contained in a FocusScope. Setting focus to true on chrome doesn’t imply that the active focus will change, it only guarantees that the next time the active focus is set on the enclosing focus scope, chrome will receive it.

So the current code that does "chrome.focus = true" in the onTriggered handler of the "find in page" action should really do "chrome.forceActiveFocus()".