If all recipes are unlocked, you cannot set the furnace to "show all" while the crafting table is on "show craftable".
To reproduce:
Create a world in 18w06a or 18w07a.
Do /recipe give @a *
Open a crafting table and set the recipe book to only show craftable items.
Open a furnace and open the recipe book.
Another route:
Create a world in 18w06a or 18w07a.
Do /recipe give @a *
Open a furnace and set the recipe book to only show craftable items.
Open a crafting table and set the recipe book to only show craftable items.
Open a furnace and change the recipe book to show all items.
I'd like to know why my issue and this issue are marked as resolved, when it clearly has not been resolved. I can't even use a furnace, period. Spawning in a new one does not work, literally cannot use a furnace period. I did not turn anything ON in the furnace, I tried to open the furnace crafting book inside, and it crashed. Nothing was turned on. Couldn't even SEE the crafting book. Ever since, furnaces are 100% completely unusable.