I recommend that you make sure that all required Telerik assemblies are referenced in the LightSwitch project and more specifically the Telerik.Windows.Themes.Vista assembly. This is applicable for both StyleManager and Implicit styles theming mechanisms. There's just one major difference runtime if the theme assembly is missing -- with StyleManager it will fallback to the default OfficeBlack theme (as in your case) and with NoXAML binaries (required for Implicit styles theming mechanism) you won't see nothing runtime simply because there is no theme resource file to render your xaml from.
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