public EditableAnnotationLayer(FlexChart chart) : base(chart)
 {
     AllowMove                      = true;
     _flexChart                     = chart;
     _flexChart.MouseDown          += OnMouseDown;
     _flexChart.MouseUp            += OnMouseUp;
     _flexChart.MouseMove          += OnMouseMove;
     _flexChart.MouseDoubleClick   += OnMouseDoubleClick;
     _flexChart.Rendered           += OnChartRendered;
     _flexChart.ControlRemoved     += (s, e) => chart.Focus();
     Annotations.CollectionChanged += OnCollectionChanged;
     _rectCache                     = new List <AnnotationEx>();
     SelectionStyle                 = new ChartStyle
     {
         Stroke            = Brushes.Red,
         StrokeDashPattern = new float[] { 3, 2 },
         StrokeWidth       = 1
     };
     Attachment = AnnotationAttachment.Absolute;
 }