Can't bind programs to ctrl+shift+(key)

I try to bind Photoshop to ctrl+shift+P and it doesn't work. I can use ctrl+alt+P but that requires to hands as I push ctrl+alt with my left ring finger and index finger. When I use ctrl+shift I use my ring finger and middle finger to press them while using my index to push the third key. So I'm thinking something else is binded to ctrl+alt+P, but when I press them, nothing happens so why isn't it letting me bind those three?

Is this what you are doing: Create keyboard shortcuts to open programs

I just tried it and it works okay.