Hi,
The closest feature is called Plot Bands and you can see how to use it in the following article: http://docs.telerik.com/devtools/aspnet-ajax/controls/htmlchart/functionality/plot-bands. Note, however, that it draws a colored section across the entire chart and does not create a single rectangle. Thus, you may want to play around with colors and opacity to see if you can get the desired appearance.
Regards,
Telerik
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