When searching using diacritical characters, ćčšđž, the search should also hit csdz as secondary search results. This works well on quicksearch results, but not on full results.
On my site at https://test.antikvarijatknjiga.hr you can try with Andric (also returns Andrić, as it should), Dorde (Đorđe), Sibenik (Šibenik), Zivotic (Životić), Covjek (Čovjek).