I'm building an app with a ribbon bar and I want to be able to paste images into the documents.  I have a Nov Text Editor in a Xamarin window on OSX El Cap.  If I copy text from e.g a Pages document the Paste icon on the ribbon activates and I can paste in no problem.  If I select an image - and I've tried images in Pages files, and graphics files: png, jpg, etc, the Paste icon stays disabled.  I can't see what I'm doing wrong.  I've not changed anything on the ribbon so I guess it is using the internal PasteCommand - I've not touched that, and it works with text.  Any help appreciated.

Neil