I have two ChartView, one displaying moving average indicators and the other displaying other technical indicators, which have the same timeline.

How can I using one RangeSelector to control the two ChartView at the same time.

Hello, Steve,   

RadRangeSelector is designed to be associated only with a single RadChartView at a time. It can't be associated with multiple charts simultaneously: https://docs.telerik.com/devtools/winforms/controls/rangeselector/integration-with-radchartview 

However, you can associated a single RadChartView with the range selector and synchronize multiple charts when one of them is zoomed. Knowing the current zoom factor of a particular chart, you can zoom another chart with the same value if the axis range are similar. Please refer to the following forum post which demonstrates a sample approach on this topic: https://www.telerik.com/forums/visible-range-after-zoom-in#8y4iEWfBxUCNoRQKPbXkZA   

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik