2 things :
Allow to remove wielded tools/weapons/items from the hotbar. (for now, say you have a repair hammer in the hotbar and your character currently wield it, you cannot remove it from the hotbar. you must quit the inventory screen, unwield it, re-enter the inventory and move it to a chest/elsewhere. It is incredibly frustrating at times.
When equipping a “recipe” in the hotbar (i.e building wall recipe) it cannot be unequipped very easily. IT should be as easy to unequip as “empty” hotbar slots with “ghosts item” (i.e you put a stack of walls in the hotbar, place them all, there remain a “ghost wall” in that slot that can be unequipped)