Why in many themes my menus are too white (text and background)?

view full story

http://askubuntu.com – I started using Lubuntu (12.04) and I like the customizations that I was able to make, especially fitting icons and themes ('Widgets' - as 'Customize Look and Feel' calls them.) But for some reason about a half of the themes make my menus display a pale font on a whitish background - and look unclear. So, I am stuck with customizations involving themes that are darker or that otherwise don't lead to this. I am aware only of some but important menus that are affected by this, like the Main menus, Right-click context menus of File browsers and the Firefox right-click and drop-down menus. The (HowTos)