P: (Masking) Add Sky Blue, and Sky Not Blue Selections

[GoldingD]

Request for change. In the Landscape Mask selections, in addition to the Sky, add selections for Sky Blue and Sky Not Blue. First one would select AI Sky, but would be intersected to the color Blue (as such the mask would not include clouds), and the other would invert the intersect to the color Blue (as such the mask would only include clouds, i.e., not blue)