filter on price, word search, and filter reset not working as expected

-- url of the page with the problem -- : antiqueswan.com/product
-- HikaShop version -- : 4.2.1
-- Joomla version -- : 3.9.11
-- PHP version -- : 7.2

Hi,
This site: antiqueswan.com/product , is having numerous issues with the filter and search. I did a few screen recordings in hopes to make the explanation clear and demonstrated. To summarize:

1.
Filter on price (currently a checkbox type): the selection does not remain visible to the user. Recording: screencast-o-matic.com/watch/cqQVbptOTJ and screencast-o-matic.com/watch/cqQVbdtOO6

2.
Reset: clears the fields in the module but does not reload the products so the only option if for the user to reload the menu item (and this is unlikely to be a known step for the user). Shown in other recordings listed above.

3.
Word search: creates an "aw snap - can't open this page" error page (in Chrome) after clicking return or clicking on filter button and causes all other open browser windows to do the same simultaneously. Recording: screencast-o-matic.com/watch/cqQVbptOTJ

4.
Word search: does not submit when using the keyboard return in Safari. Recording: screencast-o-matic.com/watch/cqQVF1tOte

5.
Price checkbox filter: unable to change the type from checkbox to radio button; results in "1054 Unknown column 'input' in 'field list'" and checkbox clears after user selection. Recording: screencast-o-matic.com/watch/cqQVb9tOO4 and screencast-o-matic.com/watch/cqQVFptOUX

I read the following two threads but did not find a related solution.
www.hikashop.com/forum/product-category-...r-search.html#310333
www.hikashop.com/forum/product-category-...-filters.html#310173

I sure hope you can help.

Thank you,

Karen

Thank you for the direction Nicolas. That had us headed in the right direction and took less time looking for a needle in a hay stack.

To close the loop on this issue, and perhaps for others who may be troubleshooting, I wanted to add what we found to fix it: There is some logic and javascript in the layout files. Apparently, in the case of listing.php, some changes were made that broke backward compatibility. This seemed to be a consequence of not separating logic from layout. So our overriding file fell out-of-sync with some aspect of Hikashop. We replaced the listing.php file with the new one and then added back the customizations that were there originally in the listing.php file.

Things seemed to be working as expected again.

Thank you.