The initial view of a PDF document can be tweaked. Is it a secret of PDF file? Well, we are not sure about this, and very few pieces of software can tweak PDF files. With the software utility Tweak PDF, you are allowed to set the initial view preferences of a PDF document, such as whether to center window of the PDF file when opened, whether to display document title, to fit window, to hide menubar, to hide toolbar, and to hide window UI. When window UI is made hidden, a PDF file is just like a PowerPoint slide zoomed to full screen. You can even set the page mode of a PDF document, such as show PDF files in full screen mode, outlines mode, thumbnail mode, or simply without any special mode. Page Layout also comes as an option for you to tweak. PDF document properties such as title, subject, author, keywords can be modified with Tweak PDF. You can even tweak PDF version, i.e. upgrade or downgrade amonst 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 (ISO Standard ISO 32000-1), and 2.0 (ISO 32000-2) for compatibility concerns, and shrink PDF files by setting the compression level and choosing the compression algorithm.