I am running Win 7 Pro SP1 64-bit ... my user account has admin priv.'s ...

Yup ... I clicked on the 'Hide' button to see what it meant / did exactly ...

I have been in to Settings > Dialogs and placed a check mark in the 'Show various non-critical dialogs (except for those disabled below)'
and then, below, in Setting: File Scan, I removed the check marks in the two boxes: 'Offer to clean files.' & 'Warn when adding huge amounts of files.'

Nothing I have done has restored the 'Cleaned up temporary files' dialog in the System Scan app.

Will it just magically re-appear in due course? When there are sufficient temp files to merit it?

Thanks, FFF