RadWindow can be displayed in two modes - as a normal window or as a modal dialog window.
In the first case, the UI behind the RadWindow is still active. To open it as a normal window you have to call the Show() method of the RadWindow instance.
Example 1: Showing a window
RadWindow radWindow = new RadWindow(); radWindow.Show();
Dim radWindow As New RadWindow() radWindow.Show()
To show the window as a modal dialog call the ShowDialog() method. In this case, the UI behind the RadWindow gets inactive and cannot be used until the window is closed.
Example 2: Showing a dialog
RadWindow radWindow = new RadWindow(); radWindow.ShowDialog();
Dim radWindow As New RadWindow() radWindow.ShowDialog()
When opened as a modal dialog the RadWindow covers the UI behind it with a background. You can modify the color of this background via the ModalBackground property of the RadWindow.