Can't grab or resize block anymore.

I started up hammer and created a block. I can’t grab it or resize it with the selection tool. I’m really unsure what to do.

Can you post in the Question Megathread please? You might find more help there.

Ok, thanks for the tip.

[editline]18th June 2013[/editline]

I’ve create two maps since yesterday, and today the block tool doesn’t create blocks. I’m thinking I’ve accidentally ticked a setting or option somewhere.