Configuring Authentication and Security - Mastering phpMyAdmin 3.4 for Effective MySQL Management - page 29

In the previous example, an arbitrary string of characters was used; this string can
be very complex as nobody will ever need to type it on a login panel. If we fail to
configure this directive, a random secret string is generated by phpMyAdmin but
it will last only for the current working session. Therefore, some features such as
recalling the previous username on the login panel won't be available.
Then, for each server-specific section, use the following:
$cfg['Servers'][$i]['auth_type'] = 'cookie';
The next time we start phpMyAdmin, we will see the login panel as shown in the
following screenshot:
By default, phpMyAdmin displays (in the login panel) the last username for which
a successful login was achieved for this particular server, as retrieved from the
permanent cookie. If this behavior is not acceptable (someone else who logs in
from the same workstation should not see the previous username), we can set the
following parameter to FALSE :
$cfg['LoginCookieRecall'] = FALSE;