To be able to style the menu backgrounds independently from the top level
Meaning, you can have a transparent (no background) on the top level, but then have a color background on the drop downs. This is NECESSARY all the time, because the drop downs can get lost on top of an image or color that may appear lower on the page. By having them style together, you have to break your page design - so people can see the text in the drop down menus. So frustrating .

Until we do develop this ability, I would recommend trying the following trick:
Create a solid color image that will be used as the “background color”.
Add the image as an icon to the pages you wish to contain a background – In the “Pages & Navigation” panel.
In the menu, choose to display icons centered.
Please let us know if this works for you, as we know this is not an “elegant” solution…
Thanks you.