Don't work when inspector is a seperate window

[LoicGoyet]

When the my dev tool is in separate window and the focus is on it (and not on the page itself), the shortcuts don't work. I have to focus on the page, then the shortcut works and put the focus on the dev tool window.

I've made a tiny screen cast to make me clear

It's not a real bug, but I guess it could be an great improvement make work the shortcut when the dev tool is a standalone window because the actual behave can be quite confusing.

[otravers]

I can replicate that with Canary on Windows 10, in practice the extension really works for me only in docked mode.