<Style x:Key="AppointmentItemBaseStyle" TargetType="telerik_GeneralScheduleView:AppointmentItem">
            <Setter Property="Background" Value="{Binding Converter={StaticResource AppointmentToActivityWrapperColor}}" />
            <Setter Property="BorderBrush" Value="{StaticResource RadScheduleForeground}" />
            <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            <Setter Property="VerticalContentAlignment" Value="Stretch" />
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="BorderThickness" Value="1" />
            <Setter Property="Padding" Value="2 0 0 0" />
            <Setter Property="ContentTemplate" Value="{StaticResource AppointmentItemTemplate}" />
            <Setter Property="Template" Value="{StaticResource AppointmentItemHorizontalControlTemplate}" />
            <Setter Property="Canvas.ZIndex" Value="1" />
        </Style>

The converter

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
     {
         try
         {
             AppointmentItemProxy aip = value as AppointmentItemProxy;
             if (aip != null)
             {
                 ActivityWrapper aw = ((ActivityWrapper)aip.Appointment);
                 if(aw.IsEnabled)
                     return aw.Color;
                 else
                     return new SolidColorBrush(Colors.LightGray);
             }
             else
                 return new SolidColorBrush(Colors.LightGray);
         }
         catch (Exception ex)
         {
             LoggingManager.Error("Module.ActivitySet.Silverlight", "AptmColorToBackgroundConverter", "Convert", "General failure", ex);
             return null;
         }
     }
However, when I scroll in the schedule view, or edit some appointment, the colors of the Apppointments interchange erroneously-
I believe there is some bug in the control, because the bounded objects keep their state.

Can you acknowledge and provide any solution? Thank you, Francisco