Color for added/modified lines?

In IDE Settings > Colors and Fonts > General, I have "Added Lines" and "Modified Lines" set to a light pink background. The preview window correctly reflects this change. Unfortunately, in my editor windows, for both Java and text files, added and modified lines show up the same as all other lines.

I've quit and restarted IDEA, started a new project and edited files in that project, and the added/modified lines still don't have the background. My other changes in that tab (like "Selection") and in the Java tab (like "Line Comment" and "Block Comment") show up fine.

Is this setting broken, or is there something I can troubleshoot that might get it working, or...?

Thanks.