This is a bugfix version. I changed the method of doing linked fields in the middle of writing the contribution and failed to adjust the code in the extra_fields.php administration file to the new method. You will get an error if you attempt to unlink fields or if you try to delete a field that is linked to another field. This version fixes the problem.

A complete version of the contribution is attached. If you have already installed version 2.0 you only need to replace the admin/extra_fields.php file with the corrected version contained here.

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