Mozilla 1.2.1 on Win98: mail prefs

Hello,

I've a strange behavior with the Mozilla mail reader. "Before", I had 
mail with "html headers": email adresses were "clickable" with a '+' 
sign when too much adresses were given. I could create a filter from a 
message directly, and so and so on.
But, for a while, I do not have any of those funcions... Any help would 
be appreciated.

Thanks a lot,
Philippe