While the Chart / EasyCharts are nice at face value, when you go to actually use them to look at your data, they fall apart due to some distinct limitations of the JFreeChart component. This has been a consistent complaint from customers as well.

The most obvious limitation is its lack of being able to pull data from either side of the chart period, outside the period bounds. This means that trend lines are left hanging mid-air if your chart tags don't have fast sample rates.

See example screenshot, where the light grey tag plot line is simply floating in the middle-right of the chart, as the next data points are outside of the chart range bounds. The Agitator status pen which should be in the bottom plot is simply not even displayed, as again, there are no data points for it within the chart range (despite there being data points either side of the chart window). This is very confusing and frustrating to operators.

Also, the x-trace cursor stops moving at gaps in data, but if you have multiple pens and the other pens have continuous data, the x-trace line still stops at the pen with gaps. If you have multiple sub-plots, things get even more disjointed. See screenshot.

The only real fix for this is to force all of your tags to sample values at least every x minutes, where x depends on how close you want to zoom into the chart. But this has the obvious downside of requiring more hdd space, and defeating the purpose of deadbands.