If you have a skin with a dark background color or image, there are conditions under which the new Telerik editor will pick up that dark background, but not change the text color from the default black. As a result you have black text on a dark background which makes editing hard. After trying a number of offered solutions to no effect, the one I found that worked involves editing the skin file and a bit more. If you have access to the skin file, this is an effective solution.

http://blogs.xd.com.au/20...or-background-color/