I want to have a MarkerBrush based on a property of the data object being bound to. For example,
```
class MyDataPoint
{
public DateTime XValue {get;set;}
public double YValue {get;set;}
public bool IsRed {get; set;}
}
```
I want all points where IsRed=true to be rendered red, and blue when false. Is it possible?
I've made a Style with TargetType IndicatorItem and used DataTriggers but the style is always overridden with the default marker colour,