I'm very much new to mac platforms... I'm not quite sure if files and apps actually close when I push the home button to exit. Safaripulls up the webpages I had previously been on, which is ok. But more problematic is dropbox and iannotate. With dropbox if I'm looking at file and I exit the application that file is still open when I return to dropbox. I did a test by creating a file on my PC, opening it up in dropbox on the Ipad, closing the app, then deleting the file on my PC. When I went back to dropbox on the Ipad, it said "unable to open file." So my question is, how do you close a file when you are done with it?