Problem with Newsgroups in Windows Live mail

Hi

I use WLM on a W7 x64 PC.

I have a recent problem with Newsgroups in WLM, it use to show thread all grouped under one header and I clicked on the + sign

beside the header to get the posts to expand and show separately, the click on the - sign to get the thread to close up again.

Where do I go to get the threads to show under one header again.

cheers

Daniel