[Toadling]

So perhaps the "Remaining but not available" filter could be called "Unavailable" and appear in the appropriate filter menu, indented under "Remaining", right after the "Available" option. It would essentially do the same thing as the "Remaining" filter except that it wouldn't show the next action (in purple) or any other available actions (in blue or black), leaving only those items that typically appeared in gray in Planning mode.

Does this sound right?