Definitive answer on Dyn Comp 3?

[studiojb]

I have heard and read different answers to this question and am hoping to get resolution.

When using the side-chain EQ controls, if I EQ it to the high end, is it just using the highs to trigger the compression, but still effecting the entire signal,

or

is it only effecting and compressing the high and and letting the lows pass unaffected, this behaving like a multi-band compressor?

As a further example of my question: Does it act like the de esser with the HF only selected, or with the HF only un-selected?