View difference between Paste ID: 8hb7EzZH and MNezy8wj

 ===== MainPage.xaml =====
 
 <UserControl x:Class="SilverlightApplication3.MainPage"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:oxy="clr-namespace:OxyPlot.Silverlight;assembly=OxyPlot.Silverlight"
     mc:Ignorable="d"
     d:DesignHeight="300" d:DesignWidth="400">
 
     <Grid x:Name="LayoutRoot" Background="White">
         <oxy:Plot x:Name="FFTplotter"/>
     </Grid>
 </UserControl>
 
 ===== MainPage.xaml.cs =====
 
 using System;
 using OxyPlot;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Windows.Controls;
 using System.Collections.Generic;
 
 namespace SilverlightApplication3
 {
     public partial class MainPage : UserControl, INotifyPropertyChanged
     {
         public MainPage()
         {
             InitializeComponent();
             FFTplotter.Model = new PlotModel();
             SetPlotData();
 
             SelectedValues = new ObservableCollection<int>();
 
             FFTplotter.Model.MouseDown += MouseDown;
             FFTplotter.Model.MouseUp += MouseUp;
             FFTplotter.Model.MouseMove += MouseMoved;
         }
 
         private void SetPlotData()
         {
             // Set the type of lineseries and the kind of visualization
             var ls = new LineSeries();
 
             var ps = new List<DataPoint>();
             Random random = new Random();
             var min = 0;
             var max = 100;
 
             for (int x = 0; x < 1000; x++)
             {
                 var dataPoint = 1;
                 ps.Add(new DataPoint(x, random.Next(min, max)));
             }
 
             ls.ItemsSource = ps;
 
             FFTplotter.Model.Series.Clear();
             FFTplotter.Model.Series.Add(ls);
             FFTplotter.Model.InvalidatePlot(true);
         }
 
         private ObservableCollection<int> _selectedFrequencies;
         public ObservableCollection<int> SelectedValues
         {
             get { return _selectedFrequencies; }
             set
             {
                 if (value == null) return;
                 _selectedFrequencies = value;
                 NotifyPropertyChanged("SelectedFrequencies");
             }
         }
 
         private bool _mousedown;
         private void MouseDown(object sender, OxyMouseEventArgs e)
         {
             _mousedown = true;
             e.Handled = true;
         }
 
         private void MouseUp(object sender, OxyMouseEventArgs e)
         {
             _mousedown = false;
-            RenderSelectedValue();
+            RenderSelectedValue(e);
             e.Handled = true;
         }
 
         private void MouseMoved(object sender, OxyMouseEventArgs e)
         {
             if (_mousedown)
             {
-		RenderSelectedValue();
+                RenderSelectedValue(e);
                 e.Handled = true;
             }
         }
 
         private ObservableCollection<Annotation> _selectedFrequencylines;
         private static bool RenderingLines;
-        private void RenderSelectedValue()
+
         private void RenderSelectedValue(OxyMouseEventArgs e)
         {
             if (!RenderingLines)
             {
                 RenderingLines = true;
-                if (_selectedFrequencylines == null) _selectedFrequencylines = new ObservableCollection<Annotation>();
+
                 Axis xaxis, yaxis;
-                _selectedFrequencylines.Add(new LineAnnotation
+                FFTplotter.Model.GetAxesFromPoint(e.Position, out xaxis, out yaxis);
                 if (xaxis == null) return;
                 double x = xaxis.InverseTransform(e.Position.X);
-                    X = 500,
+                var a = new LineAnnotation
                 {
                     Type = LineAnnotationType.Vertical,
-                });
+                    X = x,
                     Color = OxyColors.Gray,
-                // And plot all the added lines!
+
-                foreach (var a in _selectedFrequencylines)
+                };
 
-                    // TODO: here silverlight crashes if you quicly click (with lmb) at two different locations in the plot.
+                // Add the new line
-                    FFTplotter.Model.Annotations.Add(a);
+                FFTplotter.Model.Annotations.Add(a);
-                }
+                FFTplotter.Model.Title = FFTplotter.Model.Annotations.Count + " annotations added";
 
                 FFTplotter.Model.InvalidatePlot(false);
 
                 RenderingLines = false;
             }
             else
             {
             }
         }
 
         #region INotifyPropertyChanged Members
 
         public event PropertyChangedEventHandler PropertyChanged;
 
         /// <summary>
         ///   Generic NotifyPropertyChanged function
         /// </summary>
         /// <param name="propertyname"> Name of the property that has changed </param>
         private void NotifyPropertyChanged(string propertyname)
         {
             if (PropertyChanged != null)
             {
                 PropertyChanged(this, new PropertyChangedEventArgs(propertyname));
             }
         }
         #endregion
     }
 }