As you add more parts to a page, the flowed layout might cause some parts to be formatted to appear off the bottom of the page. A quick way to make all of the parts visible is to select Resize To Fit from the pop-up menu of the Page part.

Remember that resizing the page in this way is strictly an edit-time operation. At run time, the size of the viewable area of the page is determined by the size of the user's browser window.