Picks a random item of the ticked types currently on screen. Types whose layer is switched off are greyed out until you turn the layer on.
╔═╗╔═╗╔═╗╔╗╔╔═╗╔═╗╔╗╔╔═╗╔═╗╔╦╗╦╔═╗╔═╗╔╗╔ ║ ║╠═╝╠╣ ║║║╠═╝╠═╣║║║║ ║╠═╝ ║ ║║ ║ ║║║║ ╚═╝╩ ╚═╝╝╚╝╩ ╩ ╩╝╚╝╚═╝╩ ╩ ╩╚═╝╚═╝╝╚╝