Hi! I want to have the same set up I have in my rMBP 13" and the app Lightshoot Screenshot, which is to use ⌘⇧4 (yep, same as system's) in this app. When I try to assign it, the app says that it can't be used because it's been used by the system. But I've already disabled it from system prefs... So what's going on? I even rebooted, windows style didn't help. I swear in my laptop works, and I don't remember doing anything different.