Will add 'page'. Description: Indicates that the content within the group should appear as a logical "page" when rendering the form, such that all enabled items within the page are displayed at once, but items in subsequent groups are not displayed until the user indicates a desire to move to the 'next' group. (Header and footer items may still be displayed.) This designation may also influence pagination when printing questionnaires. If there are items at the same level as a 'page' group that are listed before the 'page' group, they will be treated as a separate page.  Header and footer groups for a questionnaire will be rendered on all pages. Add an invariant to SDC that requires that 'page' level groups can only appear as root-level items and that if any root level groups are 'page', then all root-level groups must be either 'page', 'header' or 'footer'.