furnace broken

Put the summary of the bug you're having here

*What I expected to happen was put some iron ore in to furnace with coal out comes iron.

*What actually happened was I put the iron ore in to smelt and when i try to put some coal in to burn it won't let me when I try to take the iron ore out it won't let me so i have to destroy the furnace to get it out.

Steps to Reproduce:
1.tap furnace
2.put item in to cook
3.won't let put coal in won't let take item out