Currently we don't have any property to configurate this .
If you want to disabled it , the best way is open the 'Chat.js.aspx'
find the function :
function UI_AttachUser(element)
{
element.isuserelement=true;
element.runtimeStyle.cursor='hand';
element.attachEvent('onclick',ShowUserMenu);
}
and clear the content as :
function UI_AttachUser(element)
{
}
Regards , Terry .