<chartingToolkit:Chart Title="Glucose and Target Levels" x:Name="LevelsChart">
    <chartingToolkit:StackedLineSeries>

        <chartingToolkit:SeriesDefinition Title="Actual"
                                          ItemsSource="{Binding ElementName=PatientWindow, Path=GlucoseLevels}"
                                          IndependentValuePath="Timestamp"
                                          DependentValuePath="Level" />

        <chartingToolkit:SeriesDefinition Title="Target"
                                          ItemsSource="{Binding ElementName=PatientWindow, Path=TargetLevels}"
                                          IndependentValuePath="Timestamp"
                                          DependentValuePath="Level" />
    </chartingToolkit:StackedLineSeries>

    <chartingToolkit:Chart.Axes>

        <chartingToolkit:DateTimeAxis x:Name="LevelsDateTimeAxis" Orientation="X" Minimum="{Binding ElementName=PatientWindow, Path=Minimum}" Maximum="{Binding ElementName=PatientWindow, Path=Maximum}" />

        <chartingToolkit:LinearAxis Orientation="Y" Minimum="0" Maximum="200" Interval="20" />

    </chartingToolkit:Chart.Axes>
</chartingToolkit:Chart>