All armour types are not enchantable

When attempting to enchant armour in the enchanting table, no suggestions for possible enchantments are visible. This applies to all armour types.

What I expected to happen was...:
Enchantment table suggest possible enchantments for the player to apply to the armour piece. Adding selected armour and required amount of lapis lazuli will allow enchantment. 

What actually happened was...:
Procedure followed as previously described but the enchantment window provides no suggestions for leveled enchantment. Tools behave as per usual.

Steps to Reproduce:
1. Construct full enchanting set-up
2. Select item for enchanting in the window.
3. Observe lack of enchanting options.