notification tray icon area
Uses an image defined in Title Bars and Window Frames / UIS2 Frames / Non captioned window edge / [Image] tab. On Win10 I have the best luck with a bmp or tga without any real transparency, transparency seems to leave some graphics remnants when I mouseover the icons, but you can give it a try if you like. It's a 2 part image, left and right, so if you want a 100x100 pixel square frame make the image 200 wide x 100 tall and duplicate the left and right halves. Default image count is 4 but ignore it, everyone seems to just leave it there.
background/text color of the menu
Background color is System Colors / Menu. Text color is Controls / Menus / Popup menus / Menu item / [Text]tab. As you might expect those settings will affect various other places, so it's best to keep light colors somewhat light and dark colors somewhat dark, else you will probably be chasing down other things to change.
