Notes
IMP 6, Horde 5<br />
Modifies topbar to display user id beside date.
Tested on Debian 6.0 (squeeze), Horde 5.0.3 and IMP 6.0.3.
Modification
<table class="horde-table">|| File || Variables, Function(s) |||| horde/lib/View/Topbar.php ||  |||| Last updated 2013-01-16 ||  ||</table>
Descriptions
horde/lib/View/Topbar.php
Backup your original horde/lib/View/Topbar.php. Edit Topbar.php and modify line 78:<br />
Form:
<pre><code class="language-php">
        /* Sub bar. */
        $this->date = strftime($GLOBALS['prefs']->getValue('date_format'));
</code></pre>
To:
<pre><code class="language-php">
        /* Sub bar. */
        $this->date = strftime($GLOBALS['prefs']->getValue('date_format')) . ' - ' 
            . $GLOBALS['injector']->getInstance('Horde_Core_Factory_Identity')->create()->getName();
</code></pre>
To display user name and email address:
<pre><code class="language-php">
        /* Sub bar. */
        $this->date = strftime($GLOBALS['prefs']->getValue('date_format')) . ' - ' 
            . htmlspecialchars($GLOBALS['injector']->getInstance('Horde_Core_Factory_Identity')->create()->getDefaultFromAddress(true));
</code></pre>