These two classes are specific for WMS layers provided by a THREDDS Data Server, as they use getFeatureInfo method to get an XML with the values of the layer along time (see ncWMS documentation). We recommend to use at least version 4.6.1 of TDS, which includes a significant improvement in the response time of GetFeatureInfo requests (see the issue at github).
By default, only 7 days of data are requested for each marker. When visible time range in the chart is changed, additional data is requested to the THREDDS Server.
The vertical red line represents current selected time on the map. You can change the current time by clicking on the chart (so, the chart can be used as time control as well).
You can add more timeseries to the chart double clicking on any point on the map.