Sorry, I got past the issue above and implemented it successfully. Right in front of my face. It's a terrific addition!

But I am having one problem I can't seem to solve. When I click "filter", it works well from the categories and from search pages, but it does not work when I filter from the 'Specials', 'New Products', 'Featured Products', or 'All Products' pages/queries. When filtering from these pages, it simply reloads my main page (with no products at all), even though the URL in the browser shows the SQL call.

Here are some example resulting URLs where I try the same filter from the different locations, all of which should return some matching results. The Filter is for 'Format' = 'Single'

From the "Specials" page - does not work, just shows/returns the main index page. But it keeps the URL, so it's not a redirect.
https://noernbergstamps.com/?fltForm...ngle&x=25&y=12

From the "New Products" page - does not work, just shows the main index page
https://noernbergstamps.com/?disp_or...ingle&x=20&y=2

From a page of search results: - works as expected
https://www.noernbergstamps.com/inde...ingle&x=24&y=7


The first thing I notice is that URL on the Non-Working URLs are missing the index.php?main_page=(whatever). If I manually add it to the URL, then it works. Example is:
https://noernbergstamps.com/index.ph...ingle&x=24&y=7

So, where is the code at that I can get this resulting URL to be fixed permanently?

Possibly relevant things I am using:
ZenCart 1.5.1
Ceon URL Mapping 4.4.3
Dynamic Filtering 2