Without a proper design spec it's hard for me to argue this, but in my head I was thinking of a button which creates its own UI window and injects a string property into the currently selected object without needing to hook into the formal UI itself. Your version is definitely more intuitive, though. And support for data structures would indeed render my proposed script unnecessary (assuming it supports dictionaries which can contain arrays of dictionaries... I think that's as far down as I've gone so far, I guess, but a dictionary of [data type] and array of [data type] would handle it. The UI on that could get interesting, though).