PingPlotter's graphs show the change in latency over time. If I recall my college math correctly, jitter would the derivative of latency, something that PingPlotter Pro displays.
My request is slightly different. Sometimes there is a route change or event that raises or drops the latency by several milliseconds. But it's not momentary, it stays for a long time. When I slide the graphs from left to right and allow PingPlotter to auto-adjust the y-axis it's not always obvious that this change in latency occurs, unless I would zoom out the time scale.
So my feature request is that PingPlotter somehow annotate the graph to show that a sustained change in latency occurred. This amount of change and length of time that it needs to change before it shows should be user-configurable.