In the current viewer, page position is marked in history only when new link is followed or new page is opened. Such actions are similar to the "Go" and "Back" button on IE.
But don't you feel useful if the last position before large jump (Go top, Go bottom) or search is also marked in history? You can go back and force inside the document freely without using bookmarks. I made a sample viewer with a new choice "Frequent Marking in History" in the preferences panel. Please take a look! http://www.chem.nagoya-u.ac.jp/matto/plucker/viewer_en_20020719.prc matto
