Frequency warning scope?

A film I'm working on has an annoying 17k tone that pops up on some production recordings.
I've notched out most of them, but I'm worried some may be left.

Is there a spectroscope plugin that can scan a whole mix and alert you if and when particular standing frequencies occur?

A bit like a loudness compliance plug, but for frequencies?

I have Izotope Insight which really looks as though it should be able to do that, but I haven't got it to work for me yet.

Thanks

Martin