Can't write on signs.

I'm playing on the 1.6 pre-release. Simple bug, if I place signs on fences, it doesn't give me the chance to type my message on the sign. I'm not sure if a similar issue occurs when placing signs on other fancy blocks, I just know that placing sings on normal blocks still works.

Not a new feature, it wouldn't let me change the type. Also, it's not API, sorry about that.