diff -r 3d66ca73df55 -r 9f157d9c725b src/FingersDance.Views/TimelineAnnotationView.xaml.cs
--- a/src/FingersDance.Views/TimelineAnnotationView.xaml.cs	Tue Oct 13 19:09:46 2009 +0200
+++ b/src/FingersDance.Views/TimelineAnnotationView.xaml.cs	Tue Oct 13 19:33:13 2009 +0200
@@ -11,6 +11,7 @@
 using System.Windows.Media.Imaging;
 using System.Windows.Navigation;
 using System.Windows.Shapes;
+using Microsoft.Surface.Presentation;
 
 namespace FingersDance.Views
 {
@@ -41,4 +42,17 @@
             return thickness.Left;
         }
     }
+
+    public class VisibilityConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
+        {
+            Visibility v = ((float)value>0) ? Visibility.Visible : Visibility.Hidden;
+            return v;
+        }
+        public object ConvertBack(object value, Type targetTypes, object parameter, System.Globalization.CultureInfo culture)
+        {
+            return 1.0;
+        }
+    }
 }