When using the "Find Messages" dialog, using the "Subject" field with the "contains" operator to search for emails does not work: the search returns no messages, even though the search value contains part of a name or address that exists. Using "Complete Message" or "Body of the message" does work.

Note that "Anywhere in Headers" does not work as well.

Reproducible: Always

Steps to Reproduce:
Try to search for the sender of one of your email in your inbox.
Actual Results:  
No result returned.

Expected Results:  
Emails from this sender should be returned.

The emails are stored on an IMAP server. Nepomuk is running with "Semantic Desktop" and "Email Indexing" enabled, and "File Indexing" is disabled.