how to set bottom (Cntr+c) for Joxi app (screenshot taker)

how to set bottom on mouse combination "Cntr+c" (copy) for Joxi app (screenshot taker)?
I set bottom on mouse for activating Joxi app. When I activate it and set area for shot i cannot use set bottom for Joxi app "cntr+c" (I want bottom works only when this app is active). Joxi app is running background always.
When I try to select Joxi app from "select app from running app" - there is not Joxi app in this list but this app is running background. For testing I added this app from "select app from files system".