Hello Craig Booth,
Maybe, my colleague Martin did not express himself correctly. He meant to say the feature will be included in one of our next releases, but he did not specified in which release exactly.
However, the feature that Martin concerned is already implemented, so now you can make the selected group orange by modifying the default themes. This is the best way to achieve the desired look and feel.
The key part of the custom theme is the Telerik.WinControls.UI.RadPanelBarVisualElement.Selected property that you should use in the RadPanelBarVisualElement state tabs. For additional information about Visual Style Builder, please refer to these support resources:
Creating a Theme for RadPanelBar
State Precedence Rules
I am attaching a sample theme based on the ControlDefault theme. The states that I created for the RadPanelBarVisualElement can be used as a pattern in case you want to modify other themes.
I hope this helps. if you have additional questions, feel free to contact me.
the Telerik team