Does adding the following line to file config_inc.php fix the issue?

$g_show_user_realname_threshold = ANYBODY;

I'm checking the code because I'm not able to display realnames on combo, and seems that refactoring in 2.12.0 has introduced this problem
probably with new config option, but also there is a related error on
function user_get_expanded_name_from_row(), because realname is not used

If you want I will open a new issue related to this.

Anyway IMHO, the choice of 'username (realname)' at least on combos has to be configurable and not the default as seems to be on 2.12.0

Common error write before test => the error on user_get_expanded_name_from_row() is that return value is:
realname (username) and not as described on function header:

• Get display name in format "username (realname)"

I've added $g_show_user_realname_threshold = VIEWER;

$g_show_user_realname_threshold = ANYBODY;

The problem persists

I have submitted a PR that changes timeline to use the standard API for displaying usernames
PR: https://github.com/mantisbt/mantisbt/pull/1317

This means:

• Always display usernames
• Hyperlink to user page which has more info about the user.
• Have the user realname as a bubble.
• Only show realname when $g_show_realname = ON and logged in user has access level >= $g_show_user_realname_threshold