[itimpi]

That was what I said by the fact that you cannot do the thing by clicking.

You would have started with tag:tagname in the search box which would show books with that tag type. When you see an author the add the author:authorname value as well to the search box as an additional criteria and you will be shown all book by that author with that tag.

It might be worth raising a ticket for a feature request where a right-click on an item has a menu item of "add to search criteria". Then you could get exactly what you want without typing anything in. Might want a complementary "remove frrm search critieria" entry to complete not needing to use a keyboard. In fact thinking about it I am going to head over to Kovid's site to raise such a request myself.

Edit: Done