ContextMenu using MVVM (ItemsSource) trying to find DataContext - wpf

Question

I am struggling to get this binding working on my ContextMenu.
I am using Items Source so each item is of the type frm ItemsSource, so I need to search up the tree to get the correct binding context.
The command I am trying to execute exists within the DataContext of the ContextMenu as you can see it bound here:
DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}"
So I attempt to bind to that data context using RelativeSource but no matter what I have tried I always get a binding error:
System.Windows.Data Error: 40 : BindingExpression path error: 'CreateNodeCommand' property not found on 'object' ''NodeGraphView' (Name='networkControl')'. BindingExpression:Path=DataContext.CreateNodeCommand; DataItem='ContextMenu' (Name='NodeGraphRightClickMenu'); target element is 'MenuItem' (Name=''); target property is 'Command' (type 'ICommand')
Here is the code:
<ContextMenu x:Name="NodeGraphRightClickMenu" DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}" ItemsSource="{Binding DataContext.PolymorphicTypes}">
<ContextMenu.ItemContainerStyle>
<Style TargetType="MenuItem">
<Setter Property="Command" Value="{Binding DataContext.CreateNodeCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"/>
<Setter Property="CommandParameter">
<Setter.Value>
<MultiBinding Converter="{convertersDF:Converter_MultiBindingToArray}">
<Binding Path="."></Binding>
<Binding Path="Name"></Binding>
</MultiBinding>
</Setter.Value>
</Setter>
<Setter Property="Header">
<Setter.Value>
<Binding StringFormat="Create {0}" Path="Name"></Binding>
</Setter.Value>
</Setter>
</Style>
</ContextMenu.ItemContainerStyle>
Any help much appreciated.

Answer 1

The answer was so obvious. I needed to bind to the DataContext of the DataContext. This was confusing so I have re-written it:
<ContextMenu x:Name="NodeGraphRightClickMenu" DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}" ItemsSource="{Binding PolymorphicTypes}">
<ContextMenu.ItemContainerStyle>
<Style TargetType="MenuItem">
<Setter Property="Command" Value="{Binding DataContext.CreateNodeCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"/>
<Setter Property="CommandParameter">
<Setter.Value>
<MultiBinding Converter="{convertersDF:Converter_MultiBindingToArray}">
<Binding Path="."></Binding>
<Binding Path="Name"></Binding>
</MultiBinding>
</Setter.Value>
</Setter>
<Setter Property="Header">
<Setter.Value>
<Binding StringFormat="Create {0}" Path="Name"></Binding>
</Setter.Value>
</Setter>
</Style>
</ContextMenu.ItemContainerStyle>
</ContextMenu>