When using the SmartForms Viewer Web Part on a SharePoint 2013 site in SharePoint 2010 compatibility mode, settings changed on the Web Part are not persisted. Install the SharePoint October 2013 Cumulative Update or later to resolve this issue.

The SharePoint October 2013 Cumulative Update can be downloaded from:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;2825647

If you have any issues downloading or installing the cumulative update, please contact Microsoft Support.