Thank you for contacting us. Please refer to this help article
. It basically says that the theme for the whole application has higher precedence over the theme set for a specific control. If you need different themes for different controls, you can use the code sample provided in the article I mentioned or you can set themes explicitly for every control. Please note the former is a bit more intricate for controls containing a lot of other controls e.g. RadGridView.
Do not hesitate to write us back if you have further questions. I hope your trial period is going overall fine.
the Telerik team