I'd like to echo ghost's complaint.   
Oddly perhaps, one of the many pleasures I find in ARMA is trying out new key-chord combinations, to find my optimal keyboard configuration.  But now that my LShift+P has been hijacked by "Open DLC screen" you can appreciate the frustration of engaging in online combat action, inadvertently pressing LShift+P, and having my gameplay paused by a prompt to open the Store page ... particularly when I already own all the available DLC content.  Apart from that rare event, I have better uses for LShift+P. 
With respect Bohemia, I have every intention to keep purchasing your DLC - just please relinquish LShift+P.