Easy Admin Color Schemes Causes Transparent Sub Menus Since Upgrade to WordPress 3.5

I saw someone upgrade their WordPress install to 3.5 and run into an issue where the background on menu sub menus would be transparent.  Turns out the fix was rather simple.  Go to Admin Color Schemes -> All Admin Color Schemes.  Edit under the scheme of your choice, and add the following CSS in an appropriate place (nested properly)

.wp-submenu {
background-color: #FFF
}

This fix comes thanks to philoj of the wordpress.org forum post on this issue.