Is there a restriction on the complexity of selectors that can be used with delegate in jQuery 1.4.2?

This works for me:

   $('.activeTabsList').delegate('.activeTabsListItem', 'click', 
function() { 
   alert('here'); 
});

This does not work:

    $('.activeTabsList').delegate('.activeTabsListItem:not(.selected)', 'click', 
function() { 
   alert('here'); 
});

As you can probably assume, there is only 1 item at a time that has the selected class. When I click the other tabs, my delegate handler is still not fired.