There is a problem with rotation of WPF TeeChart. It seems that you don't capture/release mouse when rotation starts/ends. Rotation will be stopped and mouse events won't be handled if the mouse is out of TeeChart borders. To reproduce the problem you only need use next code: 
c# chart code: 
  private void InitializeChart()
    {
      Steema.TeeChart.Styles.Line line = new Steema.TeeChart.Styles.Line(tChart1.Chart);
      tChart1.Axes.Left.Labels.Font.Size = 14;
      line.FillSampleValues(40);
      tChart1.Legend.Visible = false;
      Steema.TeeChart.Tools.Rotate rotationTool = new Steema.TeeChart.Tools.Rotate(tChart1.Chart);
    }
xaml code: 
<Window x:Class="TestWpf.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            xmlns:tc="clr-namespace:Steema.TeeChart.WPF;assembly=TeeChart.WPF"
            Width="600" Height="400"
            Title="MainWindow">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
          <tc:TChart Name="tChart1"/>
    </Grid>
</Window>
And follow next indication: 
To reproduce it you should move mouse with pressed button out of TChart (but not out of Window) and then release button.
Thread: http://www.teechart.net/support/viewtopic.php?f=4&t=14230&p=62665#p62656
 [created:2013-07-30T16:57:46.000+01:00 reported by:sandra@steema.com reported in version:]