Hi,
The issue may be related to the fact that Chart FX forces the same amount of points per series. When this is not the case, an unexpected behavior may be experienced. It is worth to mention that you can specify hidden points to create the illusion of some invisible points in the chart through the use of hidden points. However, although some points may be not visible, they must be present (exist) as invisible points in the series (uneven series are not supported).
In Chart FX 7 (our latest .Net product) there is a property called "InterpolateHidden" which (when set to true) allows to draw a connecting line over missing data points. When this property is set to false, hidden points in the chart will result in a "broken" line in the chart. When set to true, the chart will draw a connecting so prevent the broken line. In previous versions of Chart FX, it was not possible to create charts which markers where not evenly spaced without passing both X and Y data. The InterpolateHidden property now makes it possible to create non even spaced charts with only Y values. Additionally, please note that you can use the InitializeHidden property to instruct the chart to intialize all non-initialized values to a hidden value.
Example
To instruct the chart to draw connection lines over hidden points:
chart1.Data.InterpolateHidden = true;
Regards,
RandyJ