GTK - PYTHON at firtst
GTK Objects and Containers
In the example code above, the Gtk.Window() object self-evidently represents the GUI window, and the widget Gtk.Label is added to the object with the add()method. The add method, however, only allows a single object to be added to the window. Since you often want to put multiple widgets into a window, some sort of container object, such as Gtk.VBox, needs to be added instead. The Gtk.VBox object can contain and organize multiple widgets into a Vertical column. Similarly, the Gtk.HBox object is also available, organizing its child widgets into a Horizontal row. To create more sophisticated layouts, you can nest the container objects, i.e. have a Gtk.HBox inside a Gtk.VBox.
The use of these objects is demonstrated in the illustration on the right. The Gtk.WindowGroup object is optional, but allows your application to display more than one gtk.Window. The chapter ‘Multiple Windows’ explains how to use this; for now, we will stick to a single window.
you can find more : https://en.wikibooks.org/wiki/PyGTK_For_GUI_Programming/First_Steps\