Hello again Ernest.
I have rated your plugin, top marks 🙂
I am still having issues with this topic. Some of my posts have more than one category, so I have added a settings check box to show which. When I click off one of the categories no posts show. If they are all checked they show.
So, If I type 'Plumbers' and I uncheck the Chelmsford box I end up with one post (which has all categories). So it must be some AND logic but I have changed the logic and still nothing happens 🙁
What am I doing wrong?