What options are available for setting the Open Mode of a PDF document? May 7, 2013 / Judi / Appending/Publishing, FAQ, FAQ AppendPDF Pro The options are: OpenMode (ShowBookmarks, ShowThumbnails, ShowNone). AppendPDF Pro users may choose to show the bookmark pane, show the page thumbnails, or choose none and open the document without bookmarks or thumbnails. Adobe AcrobatAppendPDF ProInput/OutputSettings