This was actually surprisingly difficult for me to figure out since there is basically no discoverability hints anywhere, and I literally found it by accident. In the Dropbox app for iPad, if you open a Word or other Office document, there is a little button in the lower right hand corner for viewing the document in full-screen. However, if you open a PDF document, that button is not present. Hmmm… Additionally, in the iOS 5 version of the Dropbox app, there used to be an arrow button in the navigation bar area to toggle the visibility of the navigation panel on the left. This served as an adequate almost-full-screen view of a PDF, but the (as of March 10, 2014)[…]