Cannoli.ThemeChanger (nuget): This package provides a behavior that can be applied to a button or load event that will swap a running xaml theme to one specified in the behavior.  Just add System.Windows.Interactivity and drag and drop the CannoliBorderlessWindowBehavior onto your window object in Blend.  Note: You can then style that window by altering the CannoliBorderlessWindowStyle.xaml
Keywords: WPF