Mac, PPro CS5

Each secondary color correction set (for example in Three-Way CC) has at the end the option to "Invert Limit Color" (invert mask). However it does not work for me - instead of inverted selection, I get only 100% black in mask view, and no color adjustment whatsoever.

Has anyone else run into similar problems? I'm trying to establish if this is a bug, or there's something wrong with my setup.

Did you set the output to Mask?

Of course. And I did make the selection as well. Normal mask is fine, it's just when I click "Invert..." I get all black mask and in composite view no color adjustment at all.

A mask is always black and white.
If you want to see color you deselect the mask and set it to composite.
When turning the wheels you see colour changing or all except the part you masked out.

Perhaps the screenshots will better illustrate what I'm talking about. I know that mask is black and white, the problem is that when I click the button the mask disappears (is 100% black), instead of inverting.

Ah, now i see what you mean.
Perhaps a bug on the Mac version.
My output is normal.