# How to mention someone in comments if his\her name doesn't appear after typing its first letters?

Suppose there is a question of a member $A$. I want to mention this member $A$(so it appears in the comment as "@A"). sometimes,when I type the first letters of name "$A$", The name appears in a rectangle above and I click on the name so the member is mentioned. Many times, When I type the first letters , no thing happens!

What to do in this case? Can I mention him\her manually? How to do this? Suppose that his\her name was "$A\text{ } B$"(there is a space, like in "Maths Lover"). Should I type "@MathsLover" or "@Maths Lover"

Added: When I try to mention the member manually, his name disappear when I post my comment. How to deal with that?

• About your addition: meta.math.stackexchange.com/questions/6281/… Aug 21, 2014 at 13:40
• Spaces are removed from the display names for matching purposes. So to match Peter Smith you may use @pet, @peter, @peters, or @petersmith. Quote from here. Aug 21, 2014 at 13:44

When you comment under a post, the post author is always notified, so there is no need to alert her/him with an @-ping. If so far nobody except you and the post author have participated in the comment thread, an @author is automatically removed from the comment, since it is deemed clear whom you address with your comment. If you nevertheless want to explicitly address the post author, do that without an @. If other people have posted comments on the post, an @author is still not necessary to notify the author, but will not be removed, since it is now not a priori clear to whom your comment is addressed.
• Yes, the post author is always notified of comments on their posts, whether they contain an @-ping or not, and whether they are addressed at somebody else or not. (Unless the notification system is broken, which occasionally happens for some time.) Aug 21, 2014 at 13:10