Prevent specifying background color
Supported on: At least Internet Explorer 7.0
Registry
HKCU
Software\Policies\Microsoft\Internet Explorer\Settings Options
Background Color text Description
This policy setting prevents the user from specifying the background color in Internet Explorer. If you enable this policy setting, the user cannot specify the background color in Internet Explorer. You must specify the background color (for example: 192,192,192). If you disable or do not configure this policy setting, the user can specify the background color in Internet Explorer.