private void drawingManager_OnAnnotationSelect(object sender, Annotation selectedAnnotation)
 {
     this.txtAnnotationLabel.Text = selectedAnnotation.Label;
     this.txtAnnotationLabel.SelectionStart = this.txtAnnotationLabel.SelectionLength = 0;
 }
        public void Add(Annotation annotation)
        {
            DrawingAnnotation drawingAnn = null;
            foreach (var prototype in prototypes)
            {
                if (prototype.BelongsTo(annotation.Polygon))
                {
                    drawingAnn = (DrawingAnnotation)Activator.CreateInstance(prototype.GetType());
                    drawingAnn.Initialize(pictureBox);
                    drawingAnn.Annotation = annotation;
                    drawingAnn.IsSelected = false;
                    drawingAnn.ShowLabel = this.ShowLabels;
                    break;
                }
            }

            if (drawingAnn == null)
                throw new Exception("Could not determine the drawing annotation type!");

            drawingAnnotations.Add(drawingAnn);
        }