how to config PM to show "login name" not "display name"

[spiritbreaker]

i have a little problem and wish someone help.

when i want to send personal message (instant message) to member.
there is a box contain the name(s) who i what to sent message.

but it show by "display name". how i config to show "login name"
because it's my problem when member edit their display name with ' " ' charactor


ps. display name = name you can see them on webboard
    login name  = name when you regist to webboard.

THANK

sorry for my english, it's not my native language. 

[spiritbreaker]

anyone help? 

[Thantos]

Simply turn off display names:
Admin -> Feature and Options -> Allow users to edit their displayed name?

[spiritbreaker]

Simply turn off display names:
Admin -> Feature and Options -> Allow users to edit their displayed name?

thank you for reply 

but i want my member use their native language ( i'm non english native speaking )
so , maybe i could change code for edit problems, right? but i cant find them.

now i see code in [theme]/Display.template.php

i see message['member']['title'] , i think it maybe my point.
but i dont know what value of message[]

how cant i find them??

thank