Typing outside of an input box should focus the message field

[blattersturm]

Is your feature request related to a problem? Please describe.

As a user, I may navigate between pages using my mouse, and want to start typing immediately.

Describe the solution you'd like

Typing without any input box focused should focus the message field and take my input.

Describe alternatives you've considered

This is common behavior across IM apps. The alternative would be to automatically focus the input, but this seems to hit #71.

Additional context

Other applications behave similarly: even if the message input box is not focused, I can still type messages.