Thanks for the reply.
If I show a custom field on a page like this is is not encoded
<?php echo (get_post_meta($post->ID, 'email', true)); ?>
If I do the following it works (the field only contains one email):
<?php $email= (get_post_meta($post->ID, 'email', true)); ?>
<?php echo enkode_mailto("$email", "$email"); ?>
The above code works when when inserted directly in sidebar.php, BUT if I try putting the above code in a sidebar widget using the Executable PHP widget plugin the encryption doesn't work. It looks like it encodes only the "mailto:" text but it doesn't get the $email variable - possibly a path issue with the widget. The direct approach becomes sadly complicated when using an over-engineered theme like Thematic, which is why I resorted to the Executable plugin.
If I use the shortcode in a custom field I see the literal shortcode printed on the screen - nothing is encrypted - regardless of where that custom field is displayed.
I've also tried using the Links widget for contacts to put a list of people's names and email addresses in the sidebar. These emails are not encrypted either.
So .. there is some difficulty with email addresses in widgets and some difficulty with the shortcodes in custom fields.
Thanks in advance! Any suggestions or ideas are most welcome.