Hi Peter,

Although this request is for the Chart properties, I can answer in the same context because the underlying topic is the same.

This is expected and designed behavior when attempting to use a DynamicResource with a CLR property. In order for a DynamicResource to work, it relies on the target property to be a BindableProperty (or 'DependencyProperty' in other XAML flavors).

The reason this is designed this way is for performance reasons. We choose to keep the properties of these style objects to be CLR properties. For example, the DataGridBorderStyle class's properties are not BindableProperties because that can have a severe performance issue in a UI virtualized panel like the DataGrid uses.

So, the trade-off for that performance means you need to replace the style property itself, rather than update the individual values of the style's properties. For example, make the entire style object updatable:

<!-- Do This -->
<RadDataGrid  RowBackgroundStyle="{Binding SomeDynamicSourceBasedOnConditions" />

<!-- instead of this -->
<RadDataGrid>
    <RadDataGrid.RowBackgroundStyle>
        <DataGridBorderStyle BackgroundColor="{DynamicResource someDynamicThing}"  .../>
    </RadDataGrid.RowBackgroundStyle>
</RadDataGrid>

Until the framework itself doesn't impose such performance penalty for the listeners of the BindableProperties, this is the best compromise that still lets you achieve your customizations goals. 

Regards,
Lance | Manager Technical Support
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