reverse highlight

In the Help > Getting Started > Tutorials that Adobe provides with Captivate, often there is a highlight box that is transparent and the background around the highlight box is tinted with a semi-transparent color. The color lets the background around the highlight box show through, as if looking through a tinted lense. For example, you can see this effect in the Edit tutorial in slide numbers 4, 7, 10, and 32.
Can anyone explain how to achieve this effect in Captivate? (I'm using version 3)