You cannot use XValue and XCategory simultaneously.When using XValue items will be placed at the corresponding position along the X axis, XValue
should be double or DateTime. Using XCategory forces the chart to arrange the items in a sequential manner and to create a category for each item. With a large amount of data using XValue is the appropriate choice.
You can send us a sample application, which demonstrates the issues you've encountered, by opening a support ticket and attaching it. This way we would be able to assist you further.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items