@devoncarew - The question I had earlier is that there seems to be a problem with the change of setMarkers() to clean the annotation slate each time because onMarkerChange only hands out one marker at a time (via file.createMarker()).  Shall we change addMarkers back to adding, or change the event and createMarker to provide a complete list every time?  I'm guessing a case could be made for individual marker changes (so that all potential dependent views don't have to completely refresh or do a diff to see what's changed).