Hanging Signs do not break if they were placed on another Hanging Sign, and the one connected to a block is broken.

If you place a hanging sign (B) on another hanging sign (A) and then break hanging sign A, B will just float there without breaking.

What I expected to happen was...:
I thought Hanging Sign B should break! It's attached to nothing

What actually happened was...:

It just stayed there, floating

Steps to Reproduce:
1. Place a hanging sign on a block.
2. Place another hanging sign attached to the first hanging sign.
3. Break the first hanging sign!