Cannot smelt things

Put the summary of the bug you're having here

*What I expected to happen was I could place a block in the furnace (like wood), and then smelt it with coal by tapping on the box beneath it.
*What actually happened was I can place a block (like wood) in top box, but I was unable to choose the box beneath it (where coal and stuff goes).
Steps to Reproduce:
1. Begin game in survival mode
2. Continue playing game until nine (9) cobblestone blocks have been acquired.
3. Craft cobblestone blocks into furnace.
4. Acquire any number of coal items (you can smelt wood to get charcoal)
5. Place furnace down, and tap it. Place the block you want to smelt in top box. When you go to place coal in bottom box, you will find you are unable to do so.