When previewing your work on a form, you can view it by component preview or page preview.
The component preview is displayed in the Component Preview pane of the form editor. It shows the layout of the currently selected component in the component tree as it would appear on the published form.
To preview the entire form as it would appear when published, use the Page preview feature. When you use the Page preview, it displays the form in a new browser window displaying the page on which the currently selected component is displayed.