Many thanks for the prompt response. This is a very useful tip but does not resolve my particular issue.

Maybe an example would assist:-

In Tabbles I navigate to my Users\Downloads folder.

I can see all of the files and for each file I can see the default Filetype Tag ie. exe or zip.

Using the context menu I can add tags to each file in turn and can see the result in the above view.

Ideally, for any folder I would like to be able to filter or sort on the files which have no manually assigned tags.