Broken Binding

Hi

I'm having trouble with some "simple" binding.

Copied from the "Editors Integration" example I have copied the categorize button section

<RadioButton x:Name="categorizeButton" IsChecked="True" GroupName="PropertyDisplayType">
    <Image Source="/Resources/Images/Categorize16.png" Width="16" Height="16" />
</RadioButton>

<propgrid:PropertyGrid x:Name="propGrid" IsSummaryVisible="False" IsCategorized="{Binding IsChecked, ElementName=categorizeButton}" IsItemDefaultContextMenuEnabled="False">

 This gives the error

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=categorizeButton'. BindingExpression:Path=IsChecked; DataItem=null; target element is 'PropertyGrid' (Name='propertyGridEeprom'); target property is 'IsCategorized' (type 'Boolean')

I have also tried binding SortImportance from multiple PropertyGridPropertyItem's so a single item this produces a similar error

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=propPdc50'. BindingExpression:Path=SortImportance; DataItem=null; target element is 'PropertyGridPropertyItem' (Name='propPdc1000'); target property is 'SortImportance' (type 'PropertyGridSortImportance')

Using event handlers I can make it work.

I'm sure these features worked early on, may be my environment is unstable. Any suggestions would be much appreciated.

Regards

Miles