*Don't can break block with swords in creative mode"

When I went to test the pre-release 1.6, I wanted to break ground with the sword [Creative] and ... I CAN'T!

Steps to Reproduce:
1. Open a new world and switch to "Creative mode"
2. Pick up a any one sword [Gold, diamond, iron, wood or stone]
3. Hit any block with any sword and see...

Sorry but do not know much English, I'm from Argentina.

Good luck