How to fix Minecraft not reacting to pressed scroll button?
I used to be able to open a chest and press the scroll button while hovering over an item stack and it would send one of them in the chest. But when I try doing this now, it doesn't do anything. I tried looking online, no help.
Solution 1:
This feature you are describing is part of the InventoryTweaks mod. It's not in vanilla Minecraft.
EDIT: I read your question wrong. It does nothing, because you need to be in creative mode (it turns one item into a stack).