This question already has an answer here:
I just noticed some weird behaviour which I don't really understand. Maybe a bug, or is it just something I didn't get yet?
I'm refereing to this question: Porting code from Unix using Visual Studio or MingW?
In the answer there is a comment from this user
Now I wanted to ask something using the
@ to address him, but strangly his name doesn't appear in the selection box which usually appears. I entered part of the name manually, but when I submitted the comment, the name was removed from it and it appeared as if typed without it.