anchor.diff:              [<Optional;DefaultParameterValue(null)>] ?RangeColor,
               [<Optional;DefaultParameterValue(null)>] ?Labels,
               [<Optional;DefaultParameterValue(null)>] ?TextPosition,
  -            [<Optional;DefaultParameterValue(null)>] ?TextFont) =             
  +            [<Optional;DefaultParameterValue(null)>] ?TextFont,
  +            [<Optional;DefaultParameterValue(null)>] ?LowerName,
  +            [<Optional;DefaultParameterValue(null)>] ?UpperName) =            
  +            
  +        let upperName = defaultArg UpperName "upper" 
  +        let lowerName = defaultArg LowerName "lower" 
  +
           // if text position or font is set than show labels (not only when hovering)
           let changeMode = 
               let isShowMarker =
  
positive.code:         let lower = 
              Trace.initScatter (
                      TraceStyle.Scatter(X = x,Y = lower, Mode=StyleParam.Mode.Lines, ?Fillcolor=RangeColor) )               
              |> TraceStyle.TraceInfo(Showlegend=false)
              |> TraceStyle.Line(Width=0.)
              |> TraceStyle.Marker(Color=if RangeColor.IsSome then RangeColor.Value else "rgba(0,0,0,0.5)")             
  
          let upper = 
              Trace.initScatter (
                      TraceStyle.Scatter(X = x,Y = upper, Mode=StyleParam.Mode.Lines, ?Fillcolor=RangeColor, Fill=StyleParam.Fill.ToNext_y) )               
              |> TraceStyle.TraceInfo(Showlegend=false)
              |> TraceStyle.Line(Width=0.)
              |> TraceStyle.Marker(Color=if RangeColor.IsSome then RangeColor.Value else "rgba(0,0,0,0.5)")             
   
  
negative.code:             [<Optional;DefaultParameterValue(null)>] ?RangeColor,
              [<Optional;DefaultParameterValue(null)>] ?Labels,
              [<Optional;DefaultParameterValue(null)>] ?TextPosition,
              [<Optional;DefaultParameterValue(null)>] ?TextFont,
              [<Optional;DefaultParameterValue(null)>] ?LowerName,
              [<Optional;DefaultParameterValue(null)>] ?UpperName) =  
          let x,y = Seq.unzip xy
          Chart.Range(x, y, upper, lower, mode, ?Name=Name,?ShowMarkers=ShowMarkers,?Showlegend=Showlegend,?Color=Color,?RangeColor=RangeColor,?Labels=Labels,?TextPosition=TextPosition,?TextFont=TextFont,?LowerName=LowerName,?UpperName=UpperName)
  
  
      /// Emphasizes the degree of change over time and shows the relationship of the parts to a whole.
  