The game prioritizes the hotbar for certain items, but if all item stacks of that type are full in the hotbar, the game will try to put the item into the main inventory. If the item is configured to go only into the main inventory, it doesn't scan for the hotbar.
Whenever the item tries to go into the hotbar, it first fills all partial stacks of the same item, before proceeding to the main inventory, where it fills both partial stacks and empty slots. But if the main inventory is full, it doesn't check for empty hotbar slots and doesn't craft the item until there is at least one partial stack int he hotbar or one compatible slot in the main inventory. The items that don't check for the hotbar (like intermediate products) don't even try to fill partial stacks in the hotbar and will not craft if they can't fit into the main inventory.
The mouse inventory also works the same as the main inventory, so holding a partial stack in the mouse slot works (but doesn't get occupied if empty).
- The pipes couldn't be crafted, but they could easily fill the empty hotbar slot.
- factorio_2017-12-21_14-13-50.png (1.22 MiB) Viewed 2619 times
- The same goes for circuits, but those don't check for the hotbar (they could fill the partial stack in there).
- factorio_2017-12-21_14-15-00.png (1010.16 KiB) Viewed 2619 times
