This help article will demonstrate a step by step tutorial how to customize the ControlDefault theme for RadFontDropDownList.
Open VisualStyleBuilder: Start menu (Start >> Programs >> Telerik >> UI for WinForms [version] >> Tools).
Export the built-in themes in a specific folder by selecting File >> Export Built-in Themes.
Load a desired theme from the just exported files by selecting File >> Open Package
Select RadListView in Controls Structure on the left side. Then, right click to open the context menu and select DetailsView mode.
Modify the applied fill repository item for the DetailListViewVisualItem for the Current.Selected state.
Save the theme by selecting File >> Save As.
Now, you can apply your custom theme to RadFontDropDownList by using the demonstrated approach in the following link: Using custom themes
If you need to customize the elements in some of the other views, you can switch the view by right click on RadListView: