Hey, thanks for the report. This is expected behavior, not a bug. Agents Window uses its own theme set and doesn’t currently inherit the editor theme workbench.colorTheme. So even when both windows are on a light theme, the background shade can differ, which is what you’re seeing in the screenshot.
Workaround: in Agents Window, you can pick a built-in theme that’s closest to your editor theme in the appearance settings. It won’t be a perfect match, but it can reduce the difference.
There are already a couple threads about this, you can subscribe to get updates: