CodeRush is removing the single quotes that are required around some StringFormat extensions. For example:
XAMLText="{Binding Path=DraggingRows.Count, StringFormat='\{0} items'}"
becomes
XAMLText="{Binding Path=DraggingRows.Count, StringFormat={0} items}"
making it invalid XAML.
Hi Adam,
Thank you for pointing out this issue and providing code sample. I have reproduced this issue with markup extension formatting on my side. We are working on it and will notify you of our progress.