Our homepage is set to use the 3 column layout.

When I applied the background color macro to the left column of content on this page, the page rendered as 1 column when I saved.

Steps to replicate:
1. Create a page with two sections.
Top section is even, three column layout
Bottom section spans the width of the page
Save and confirm layout
Return to edit mode
2. Add content including the use of "expand" content macro and "show spaces" list macros' in the top section, left column
3. Take the top section, left column content that includes both macro types and paste it into a background color macro.
Save and see that layout is broken. Appears as page wide for all content.