The observed behavior is expected and is due to the following:
- By design the labels for the categoryAxis in grouped chart are created depending on the first group;
- The categorical charts (such as Bar, Column, Area, Line) demand a matching set of data points. Please note that the value can be null, but the record needs to be presented at the data (this is due to the fact that series.data is a simple array).
Hence in order to get all the values on the right places you should include in the data a value for the Jan 2012
. For your convenience I updated the page.
the Telerik team
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