When mail was indexed and start a search in a top folder and let search all sub folders mails not found matching the criteria (e.g. "from" contains "<part of mail address>"). This also happens if you try to find mails in the selected folder. Finding mail using the quick search lineedit for current folder works. Reproducible: Always
Please don't open same bug twice. *** This bug has been marked as a duplicate of bug 328572 ***