You can't use item while looking at fence

While looking at a fence you can not...

• Eat food
• Defend (with sword)
• Throw potion
• Drink potion
• Shoot arrow
• Throw snowball
• Throw egg
• Place entities? (boats, minecarts)
• Read books
• Throw Bottle o' Enchanting
  Etc.

This is probably due to the lead system