Comment 5 for bug 1079283

Update: I realized why the files were appearing in Dash -- Dash was not searching files, but my Shotwell library. With Shotwell library cleared, and history cleared again, the "Don't record activity" constraints were respected and the files in question no longer showed up in Dash.

This sounds like a typical culprit for users finding their "Don't record" settings are seemingly not being respected. It also adds an extra search/blacklist challenge, as it may be very desirable to include certain files or folders in e.g. a photo, video or audio program's library while excluding them from Dash search.