1 In all iframes, the green fixed-position element should not be composited.
7 "contentsOpaque": true,
11 "position": [50, 360],
13 "contentsOpaque": true,
15 "backgroundColor": "#00FFFF"
18 "position": [10, 200],
23 "position": [10, 380],
31 Composited box underneath iframe.