[@themesdefrance Participant 11 years, 11 months ago]

Hey guys,
As a theme developper I wanted to bring bbPress support and I was facing the same issue.

The plugin that @robin-w brought was working but I know something was wrong with my theme.

I managed to make it work without the plugin by deleting this snippet from functions.php :
https://codex.wordpress.org/Plugin_API/Action_Reference/pre_get_posts#Exclude_Pages_from_Search_Results

The intent of this snippet is to exclude pages from search results and I guess this was conflicting with WP4.

If you have this problem with your theme, look for “pre_get_posts” actions and if the search query is updated.

Hope that can helps 🙂