When merge tags are used as a default value, it is not saved.
Steps to reproduce the error:
1. Create a form with a text field
2. Give the field a Default Value of a Merge Tag, say Client IP address3
3. Save the form -- default value has disappeared
Normal text default values save fine. Default values of normal text and merge tags save only the normal text, except if the merge tag has normal text to the right. Weirdly, removing the normal text after first save, to leave just the merge tag, works fine.
