The quick search bar is the one thing I find exasperating about Thunderbird. The advanced search works as you would expect, but I have no idea what the quick s

The quick search bar is the one thing I find exasperating about Thunderbird. The advanced search works as you would expect, but I have no idea what the quick search is supposed to do. It does not do the one thing I'd expect it to do - a substring match on the email addresses and subject.