Remove register link from navigation when logged in

You’ll need to open up your sidebar.php file or wherever that link is, and find the code for it. You then need to replace it with something like this:

<?php
if ( is_user_logged_in() ) {
    echo 'Welcome, registered user!';
} else {
    echo '<ul class="tml-action-links">';
    echo '<li><a href="http://briddlemedia.com/login/?action=register" rel="nofollow">Register</a></li>';
    echo '<li><a href="http://briddlemedia.com/login/?action=lostpassword" rel="nofollow">Lost Password</a></li>';
    echo '</ul>';
}
?>

Basically that piece of code is saying ‘Welcome, registered user!’ if the user is logged in, and if not, gives the Register & Forget Password links currently on your site.

You may have to speak with the plug-in developer then.