Quirk with @mention

Not exactly a question, unless I included "Do you already know this?"

So I found an old post by Sam Cheung and wanted to give him an @mention.  To find him as I type out individual letters (ignore my own use of blanks):

@ S a m _ Ch e u n g

And it does find his name somewhere around the Che.  The problem is that "Sam Cheung" is his displayed name but his actual id is scheung.  So each time I entered @Sam_Cheung it would locate him quite nicely but subsequently fail to convert to a proper @mention link.  Instead I had to enter:

     @ S _ C h e u n g

So that it would properly mention Sam Cheung.

What would help with this is when the typist is offered a pick list to be able to select a person in the list.  But if I click on a person in the list, it jumps me to his/her profile.