I'm starting to get more fluent with Skyrim's creation kit, and I want to make a simple change to Devious Devices Integration's master file. The .esm file.   Every time up to this point that I have tried to make changes to an item it has been a .esp file. I hit the 'set as active file' button, becomes active file, boom, no problems.   However when trying to edit a .esm file, it adamantly refuses to set it as active, or let me save my changes. This is very problematic when editing Integration