The "Some Kind Of News" test page (in the manual tests folder) has a background dark blue background colour defined in its stylesheet, but defaults to the default black foreground colour. Once any other theme is selected from the "Colour and Contrast" UIOptions drop-down, this base theme is applied to the "Default" option, making it virtually impossible to read.

To reproduce:

1) Visit http://build.fluidproject.org/infusion/tests/manual-tests/html/SomeKindOfNews.html
2) Pull down the Display Preferences panel and choose one of the high-contrast themes (anythinig other than "Default")
3) Pull down the "Colour & Contrast" drop-down again, and see that the first entry is virtually unreadable

The "skon" theme should be adjusted to define suitable foreground and background colours, and use a different technique to accomplish the blue background on the page.