I can't designate barracks

I can't designate barracks - Things I Can't Say Out Load Book on Green Textile

According to the barracks wiki page, beds, cabinets, chests, bags, weapon racks, or armor stands can be used to make a barracks. I have built an armor and weapon rack in a room, but it is not giving me the r button option to make a barracks. What am I missing?

Screenshot showing current layout. Including selected armor stand

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