You run into some Namescope issues when trying to use elementname bindings in a tooltip, here's an alternate way to bind the series to the axes:

XAxis="{Binding RelativeSource={RelativeSource AncestorType=ig:XamDataChart, Mode=FindAncestor}, Path=Axes[(system:Int32)1]}"
    YAxis="{Binding RelativeSource={RelativeSource AncestorType=ig:XamDataChart, Mode=FindAncestor}, Path=Axes[(system:Int32)0]}"

This relies on this namespace being added to the root node:

xmlns:system="clr-namespace:System;assembly=mscorlib"

 Hope this helps!

-Graham

<

TextBlock Text="Text" Margin="0,0,0,0" >

<TextBlock.ToolTip>

<ig:XamDataChart Name="xamChartOI" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Width="400" Height="200"HorizontalZoomable="True" VerticalZoomable="True">

<

ig:XamDataChart.PlotAreaBackground>

<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">

<GradientStop Color="#FF334F79" Offset="0"/>

<GradientStop Color="#FF2EA5E4" Offset="1"/>

</LinearGradientBrush>

</ig:XamDataChart.PlotAreaBackground>

<ig:XamDataChart.Axes>

<ig:NumericYAxis x:Name="yAxisChartOI" MajorStrokeDashArray="5" MajorStrokeThickness="1" MajorStroke="White" Opacity="0.3">

<ig:NumericYAxis.LabelSettings>

<ig:AxisLabelSettings Foreground="Black" Location="OutsideLeft" ></ig:AxisLabelSettings>

</ig:NumericYAxis.LabelSettings>

</ig:NumericYAxis>

<ig:CategoryXAxis

x:Name="xAxisChartOI" MajorStrokeDashArray="5" MajorStrokeThickness="1" MajorStroke="White" ItemsSource="{Binding}" Label="{}{Label}" Opacity="0.3" >

<ig:CategoryXAxis.LabelSettings>

<ig:AxisLabelSettings Foreground="Black" Extent="55" ></ig:AxisLabelSettings>

</ig:CategoryXAxis.LabelSettings>

</ig:CategoryXAxis>

</ig:XamDataChart.Axes>

<ig:XamDataChart.Series>

<ig:ColumnSeries x:Name="SeriesTest1"

ItemsSource="{Binding}" XAxis="{Binding ElementName=xAxisChartOI}"

YAxis="{Binding ElementName=yAxisChartOI}"

ValueMemberPath="ValueCallOI" RadiusX="0" RadiusY="0" Thickness="0" Opacity="0.8">

</ig:ColumnSeries>

<ig:ColumnSeries x:Name="SeriesTest2"

ItemsSource="{Binding}" XAxis="{Binding ElementName=xAxisChartOI}"

YAxis="{Binding ElementName=yAxisChartOI}"

ValueMemberPath="ValuePutOI" Visibility="Visible" RadiusX="0" RadiusY="0" Thickness="0" Opacity="0.6">

</ig:ColumnSeries>

</ig:XamDataChart.Series>

</ig:XamDataChart>

</TextBlock.ToolTip>

</TextBlock>

As a result I see only labels on xAxis. No series, no yAxis. When I put the same xamChart on main form I see nice chart as expected.