[Request] Background input selection

[RunisDauphin]

Hi, I am Runis Dauphin from Rebelles Unis:

I think it would be a huge improvement to have the option for background input (and the option to toggle it on/off). It would be very useful to make matches in games such as Puyo Puyo Fever or Mario Kart - Super Circuit, but also for competition in Pokémon games or Megaman RPGs.
And, if possible, could you enable the posibility to have more than one configured controller (besides keyboard and controller) at the same time?

In version 0.7.1, only one of the windows can have input at the same time. I expect something similar to what I can do (or I could, if use it more) with VBA-M.

Thank you, and I hope you can implement it.