This article explains how to replace the native search bar in the Open Shop and Open Shop Pro theme by ThemeHunk.
FiboSearch plugin features built-in integration with this theme. It means you can replace the default search bars by selecting a single checkbox.
If you have activated the Open Shop theme or the child theme of Open Shop theme, you should see the following screen in the plugin settings:
Select the option
Replace all Open Shop search bars with FiboSearch and the search bar should be replaced.