[~TASK] add backend check for the firefox fix
[~TASK] add backend check for the firefox fix

ffuenf/Ffuenf_CategoryProductSortBackend,infabo/Ffuenf_CategoryProductSortBackend,infabo/Ffuenf_CategoryProductSortBackend,infabo/Ffuenf_CategoryProductSortBackend,ffuenf/Ffuenf_CategoryProductSortBackend,ffuenf/Ffuenf_CategoryProductSortBackend