Vaadin Timeline - update problem

I have a Timeline object which shows the start/end date in the upper right corner. My typical graph starts at (4 days ago) and ends at (now). Those times get converted to absolute dates when I create a graph.

Once the graph is created, I have a ‘redraw’ button which will update the graph. Since time has passed, the start/stop times are likely to be different - perhaps only by a couple of minutes depending on how long the user has been looking at the graph. When I update a graph, I collect the most recent data, replace the datasource contents with new data items and repaint the graph. My problem is that the selectedTimeRange does not seem to update. I’ve also had some problems forcing the actual graph to repaint.

Question - what do I need to do to force the displayed start/end times to be updated? I can’t access the fireDateRangeChangedEvent() routine - it is protected - but I’m guessing that is what needs to be called.
Also, I find that if I update graph #1, nothing happens, but when I update graph#2 on the page, graph #1 gets updated (sometimes, but not always)… I tried setting timeline.setImmediate(true) and that seemed to help, but not completely.

Can someone tell me the correct procedure for updating a timeline display?