I saw this was declined before due to lack of comments or feedback but i think this is good for a second round to try again. When i am revising documents for my projects, only way i can drag and drop is through page thumbnails but sifting through hundreds of pages is quicker when i can access bookmarks and click on the page to bring me to the right page i need to replace or modify. If both of the Bookmark and Page Thumbnails are able to viewed at the same time, it would make it more efficient to work with the document.