Hoping you might consider adding this choice to double click behaviors: Add All to Playing Now (play now)
I have made the following time wasting mistake more times than I can count.
In Zone: TV I carefully queue a list of videos I want to watch over the coming weeks and start a video playing on my TV.
I then switch to Zone: Desktop and get to work tagging music while I watch TV out of the corner of my eye. While tagging I often briefly play albums via Double Click: Replace Playing Now (All) to my desktop speakers to check sound quality.
Occasionally I switch Playing Now to Zone: TV to select a different video in the queue and then I forget to switch the active Playing Now back to Zone: Desktop. The next time I double click to sample an album I wipe out my carefully created queue in Zone: TV. And then I waste a bunch of time recreating the queue.
To avoid this user error I'd like to set Double Click to Add to rather than Replace Playing Now so that it does not wipe out the existing queue and I can easily recover from my error.
The problem is that all of the "Add to Playing Now" choices only act on single files and I want to double click to add an entire album.
Hence my suggestion for "Add All to Playing Now (play now)".
Another good solution would be to make Undo work for Playing Now changes.
No big deal if you don't think this would be valued by others.