A method and system in a document viewing control for laying out an invisible page grid based on various criteria, including whether the pages of a document are fixed, contain reflowable content, whether the fixed pages are all the same size, and where the user has actively focused a page when a new layout needs to be generated, which may be anytime a user changes the number of pages to display. Upon such a change, a mechanism determines page sizes based on whether the focused page has flow or fixed content. A layout mechanism computes the grid based on the number of pages (columns) to display across. For documents with mixed-sized and/or mixed flow and fixed pages, rows of the grid are determined from the active page to the start of the document, and from the active page's row to the end of the document. The grid provides consistent viewing results.