[0.17] Alt preview in furnaces disappears when it is not smelting

[msclrhd]

Steps to reproduce:
1. Place a stone furnace down on the map next to a burner miner mining iron.
2. Press Alt.
3. Add coal to the miner and furnace.
4. Click on the furnace to see it progress smeling the iron ore.
5. Wait for the burner miner to run out of fuel, but the furnace to still have fuel.

Observations:

At step 3 and 4, the furnace will display the iron plate image, then not display it for a short period of time. From step 4 (and 5 as the furnace is finished smelting at this point) it is clear that it only shows the iron plate while it is smelting, even if it has iron plate in the output slot.

Expected Behaviour:

The stone furnace should show the smelted product (e.g. iron plate) in the alt image location when either a) smelting, and/or b) containing the product in the output slot.

[alexbaucom17]

I can confirm that I have the same issue. I didn't make the connection that it is when the furnace stopped smelting until reading this post.

I took a screen recording of it, but it is having trouble uploading.

[Rseding91]

Thanks for the report however that's working correctly and also works that way in 0.16.