Chart Modes
The Easy Chart has a Chart Modes property that changes the behavior of the chart in several ways.
Historical
This mode places a date range selector at the bottom of the chart. This mode allows users to select a start and end date for the trends. The data density is shown at the bottom of the chart: the more vibrant the color, the higher the density. This the default mode, and commonly used in situations where users need to look at specific date ranges. It is important to remember that the chart does not poll in this mode. New values are only added to the chart when the selection box is moved or re-sized.

Realtime
Displays the most recent data for each pen. Users are able determine how far back in time the trend should display with the spinner and drop down at the bottom of the chart. In this mode, the chart polls for data at the rate specified by the Poll Rate property.
In some cases, you may notice that the most recent values on tag pens tend to flat-line, and then 'snap' to a different value. This is generally due to how often the chart polls versus how often history is being generated. If the chart polls at a 1,000ms rate, but history is only recorded at a 10,000ms rate, then the chart will extrapolate the last recorded value for 9,000ms. After a new value is recorded, the next poll will return the latest value, and the flat-line will change position.

Manual
Similar to the Historical mode in that trends range from two points in time. However there is not a built-in method for users to change the data range. Instead, some sort of binding can be applied to the chart's Start Date and End Date property. This mode is generally used in situations where only certain date ranges should be shown, such as values recorded during the previous day, or shift.
