void OnBreakpointRemoved(object sender, BreakpointEventArgs args)
 {
     if (args.Breakpoint.FileName == ContentName)
         se.View.ClearBreakpointAt (args.Breakpoint.Line - 1);
 }
 void OnBreakpointAdded(object sender, BreakpointEventArgs args)
 {
     if (args.Breakpoint.FileName == ContentName)
         se.View.ShowBreakpointAt (args.Breakpoint.Line - 1);
 }