Change Minecraft name?

I wanted to change my name to Minecraft but it does not work. I went to the Minecraft site and then to profile. You can then change username below, but whenever I change the page hangs up. But I can still go to other pages.

Is that the same with someone?

Unfortunately you can't easily change your name in the windows (Minecraft) account. There's the option "buy new user name"! Have I ever annoyed about it…