I have Movie Studio 8 and I put my Green Background on the Overlay Track.
Then I put my Video on the Video Track under it.

I pick Croma Keyer and Drag the Green Screen up to the overlay Track.
Then the Croma Keya screen opens and I see the 3. Sliders.

A High Therashold
A Low Therashold
A Blur.

So I play with the sliders and mass around and I thought if I then pick the EyeDroper I can pick the Green on the Video.

And it does not change the Slider settings.

How do I use this?