Something I've been wanting to do, is hide the themeselector on the profile page -- only for normal users. This allows me to choose a default theme for a new user and they can never change it.
1) Go to: /moodleroot/user/editlib.php
2) Close to the end of the file, you will see this code:
if (!empty($CFG->allowuserthemes))
{
$choices = array();
$choices[''] = get_string('default');
$themes = get_list_of_themes();
foreach ($themes as $key=>$theme) {
if (empty($theme->hidefromselector)) {
$choices[$key] = $theme->name;
}
}
$mform->addElement('select', 'theme', get_string('preferredtheme'), $choices);
}
3) All we are going to do is add an extra statement within the "if", to check also if the user is an admin:
if (!empty($CFG->allowuserthemes) && is_siteadmin($user))
4) And voila! Only admins can see that field on the profile page now.