This scenario verifies that the cyan "container" element scrolls properly with squashing enabled. The "container" element should not squash into a composited layer mapping owned by the fixed position layer or its descendant, since this would make it behave like a fixed position element during composited scrolling.

CASE 1, original layer tree:

CASE 2, scrolling y to 80, the "container" element should remain positioned with respect to the scrolled document, the fixed-pos layer compensates for the new scroll position: