Today I spent too much time with an issue that is not really documented. After having created my WPF application and changed the main window to be of the type RadWindow, my application would start, but no window was showing.
Strange..., because the application icon showed up in the taskbar.
The problem lies with the implicit styles "mode" that seems to be the new default mode for applying a theme. It seems, that the main Window doesn't get this style set automatically, even though in the designer it works as expected. Solution
The solution to the problem is simple. Add the following property to your XAML code of your RadWindow
After you added this line, the window will show up correctly.