I think that whether an App closes or opens back up at the same spot it left off has something to do with the particular App. For example: I can "close" my browser by pressing the Home Screen button and then "open" the App again by pressing the icon and it will display the same page I was on before I closed it. Unfortunately, Docs to Go does not seem to support this option. However, Mobile Office Suite Suite Pro does. You can work on a document and hit the Home Screen button and then "open" Office Suite Pro and it will go right back to whatever document, spreadsheet etc. that you are working on. Here is a link to an older version that should work with Dingo:
http://www.4shared.com/file/vGUhMw7D...itePro303.html