Adds a widget to the inside of the window.
The background of the window.
Operations for rendering user data, if the widget does not provide such.
Whether to show the title of the window to handle the movement of the window.
Widget theme.
Window title.
The width of the title bar of the window.
Available width of the widget.
Available height of the widget.
Resize the widget.
The relative position of the widget. Serves for relative positioning of the widget relative to another or its own object.
Mini-window aka the context for widgets with which you can personalize the widget panel for the theme and move (or not move) such a panel.