The concept of the transparent theme is as follows :
The telerik control is transparent and this way the final appearance depends on the background set behind the control .
Such demo you may find here : http://blogs.telerik.com/kalinmilanov/posts/10-06-09/how_do_you_see_something_which_is_transparent.aspx
There is a small online demo app in the blog. On the left, there is a color picker . You can click on the different colors and test the appearance with different colors.
In general all you need to do is just place a border behind the transparent telerik control. Setting different colors to this border should do the trick .
the Telerik team
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