after a lengthy furlough... or sabbatical... or escape...
they've always worked, but you had to know the username you were mentioning including its case, space, or special character. the little drop box 'atwho' suggestion was broken.
i finally figured it out.
hold shift hit refresh... have at 'em.... type @ and a couple letters of the users name, and it will suggest the rest for you to select. or should... it better, by dang.
I don't know if bringing the alerts thing back is worth it... what says you?