RadChart does not provide support for implicit styling as the rest of our controls due to the specifics and limitations of its theming mechanism.
So you have two options at the moment if your project uses RadChart:

• Keep the old styling mechanism with StyleManager and do not use implicit styling for all controls.
• Migrate your charting code from RadChart to RadChartView and use implicit styling.
  Here you will find some of the most important highlights of RadChartView that might help you in deciding whether to migrate to RadChartView(we would also assist you in the process, should you have any specific problems).