Can't tag friends in photos and some other areas

About two days ago, I started noticing, in tagging and some areas where I need to enter the name of a "friend", that it would not pop up their FB name in a box, acknowledging they are an FB user and one who is friends with me. I moved to the new interface a couple of weeks ago and can't think of any changes I've made to cause this. Firefox 4.0b8 (yes, a beta but it was working fine until a couple days ago). Also Windows 7 Home Premium 64 bit.) It work in some areas and not others. Sorry I can't be more specific.

It work in some areas and not others.

What do you mean by this ?

I mean that it doesn't replace my typing with the familiar little "cell" containing the name of a Facebook user. I just type in the full name and nothing happens and it won't let me click through and tag properly. In some other areas, as well, it won't pop up the acknowledged FB user name. Don't know how else to explain. Normally, when you type in a friend's name it acknowledges by creating a little grey cell containing the name. Thanks.

Sorry, Ruby. I meant I'll have the problem in tagging friends in pictures but not, maybe, in addressing a message, for example.

Have you tried any other web browser that isn't Firefox yet?