Word 2007 running on Win10


Document has editors comments, so I have used scroll bar at bottom of window to view comment balloons. All of text is still visible in window, but not the left margin. After a few minutes of no activity on my part, the page automatically shifts, adjusting the view, obscuring the comment balloons, and exposing all of the left margin. It does this over and over. Should it not stay were I place the scroll bar? Please advise how to stop this?