lightA.jpg is a visual example of what we can do with such tool.

The concept is having a Behavior or Layer Item

that is similar to the Mesh Expand property and visual contour (lightB.jpg yellow outline).

But, with it, you'll be able to:
- Shrink the "Mesh Expand" to negative values
- Move it vertically or horizontally
- Chose a color for the inner and outer part of it
- Chose the color mode (Normal/ multiply / color burn / etc)