Sections do not render transparent in Google Chrome and Firefox browsers when a background picture set using page setting in WordPress. The same happens for background color when set in X-Options-Layout and Design and/or background image.
The following is the version of simple test page using Cornerstone in Safari and Firefox:
As you can see the Section is not displayed as transparent nor allowing the dynamic scroll of sections over the picture.
Any suggestions are most welcomed as no settings in WP, WP-X and Cornerstone seems to resolve this issue.