I tend to "sell similar" so that the new system doesn't repopulate. But lately I've been doing that from other people's sold listings if I don't have something in the same category(s).
I'm not sure what the whole purpose is, you'd think they'd announce what they are doing but they've become more secretive than the Freemason's lately.
I checked into what you might be trying to say... I searched: Books>Nonfiction and examined the filters on the left hand side of the page. Under More refinements . . . a pop up box appeared with some of the item specifics having filters.
For example, I could dial down to hymnals but not history.
I've been seeing this kind of database arrangement on a number of sites recently and hopefully this is still in transition.
Because History should be able to be checked off and then another list of filters should appear that include period and region so I can return just Non Fiction histories of the US between 1860 and 1900. Maybe even to the point of filtering the Civil War from the Indian Wars and Industrial Revolution.
