Thank you for replying.
What you say seems so obvious and straight forward. But I have tried it, both before I posted my query, and in response to your reply!
When I create the Author drop down, I connect the dropdown to the dataset for Author (which has just two fields: the Title which is the key, and the Author name). I select the author name field. When I test the page (from the editor, or on the ‘live’ site), the drop down is empty, and nothing happens. To be clear, the options you get in the dialogue box is a choice of dataset, and then the field in that dataset. I select the Author dataset, and the Author name (not the key) field. When I preview the website, nothing happens, that is, the drop box is empty. [Is there any way to debug what is actually happening?] There is another option in the dialog that at this stage I have not touched. That is to ‘connect dropdown list items’. If I switch that on, I then get another request to select a dataset and field. Am I supposed to fill those in? And if so, with what? If I choose the author dataset and author name fields (again), still nothing happens: the drop down box is empty. So I am exactly where I was before: I cannot get past the first, seemingly obvious step, to be able to filter the next dataset.
At this stage, I tried to go on and test the filter anyway. But when I try to wire it up, the dialog does not let me choose the drop down box as the source of the value ti filter on, because it is already wired up to the author dataset. And if I just select the articles field ‘contains’ the value from the author dataset, I still get nothing.
So, it is not working, despite seeming to be obvious, and I really don’t know what the problem is.