New option "Visually link expanded folders to their contents"

[AlbatorV]

Continuing the discussion from Directory Opus 13.18.1:

@Jon

Added File Displays / Folder Expansion / Visually link expanded folders to their contents options. Controls whether or not expanded sub-folders are shown with the same background color as their inline contents.

When I enable this new option, I don't see any change.
Can you explain and see what it should do?

[Leo]

It only affects modes like Thumbnails that can't indent nested content and use a different background color for it instead.