Results are removed before marker is off map

Using the 2008-Jun-11 release, the results text below the map updates as the map is moved around. When a marker is moved off the map, my understanding is that the corresponding result will be removed. However, on my map (sized 600x800), markers don't have to move off the map before their result text is gone. I wonder if that's happening when I'm within 50-miles of the marker? Either way, the marker isn't off the edge of the map yet before the result text is gone.