block class only affecting title

I have added a class to my menu-block so that I can get a border around the block. But only the title seems to be targeted. This is happening in both Firefox and Safari. Firebug can't seem to 'see' the menu-block links as a block so I'm challenged as to how to actually target the block. Other blocks on my site are appearing as I expect (with a border around them). Any suggestions appreciated!