Issue: wiki search engine does not show articles which contain the search term

Press enter to submit the search, or click the magnifying glass. The drop-down only shows articles "Starting with" as it is like an auto-complete feature, which I think works the way users would expect. To perform a full-text search you must actually submit the query.

If the search term doesn't return expected results when the search is submitted, that may be another issue entirely (such as pages not getting indexed during creation, or not updated for imported edits).