Quote Originally Posted by Arel View Post
(hint, put your pots and wands in your hotbars, if a wand's about to go out put its replacement nearby)
fyi as of u11 when the last of an item stack is used it either:

1. remains in your hotbar space but greyed out, if the same item is purchased/found future it will be available in the same hotbar space
2. if you have another stack of the item in your inv this will be placed in the same palce on your hotbar as the item that was just used up

this also works when you sell something accidentally and then buy back.

not tested if it works for spells you've swapped out and then re-slotted.