Lock overlay CSS class name

Description

Specify the CSS class name to use for the overlay that is displayed behind the window. The overlay prevents the user from clicking on controls that are outside the window. Leave blank, or specify <Default> to use the default style. Specify <Invisible> to create an invisible overlay (has no color, but user still prevented from clicking on controls off the window). By specifying a class that has a 'background' attribute, you can control the color of the overlay. For example: background: rgba(0,0,0,0) to create a transparent overlay.