The workaround for most search deficiencies is to go to Google advanced search, limit results to the ZUG URL, and use the Google search commands. You pick up results in how-to's etc. as well as in the forums, but that may often be a benefit.
The problems I've noticed with the native Forum Search include the "OR" default, which prevents you from narrowing searches, the refusal to search for three-letter words, i.e., XQt, and the inability to use quotes to search for a phrase.
If any of this can be improved without too much trouble by changing some configuration files, it would be appreciated.