I read that and my settings are exactly the same. But in your demo site, I still cannot see how the fields 'change' when the tags are selected in that demo. I only have one category...could that be a problem?... but I doubt this because in your demo the tags (women,shoes,men,dress), and SIZE, COLOUR and BRAND fields give page results which are all in one category.
It is possible to get a copy of your demo site so i can reproduce all the examples?