This is the small dialogue that is summoned by the "More Preview Options" button on the "Icons" page. Previously:
there was no margin around either the scrolling list of the dialogue buttons. The revised layout:
has margins added where appropriate.
The background colour of the scroll view is forced to the standard system background. This does not appear to be an issue with the Breeze style, but with older styles the scroll view background seems to be use the window background colour rather than the configured view background colour.