objgraph.dot

digraph G {
    root = "root";
    splines = true;

    root -> bar;
    root -> group;
    root -> layout;
    root -> screen;
    root -> widget;
    root -> window;

    bar -> screen;

    group -> layout;
    group -> screen;
    group -> window;

    layout -> group;
    layout -> screen;
    layout -> window;

    screen -> bar;
    screen -> layout;
    screen -> window;

    widget -> bar;
    widget -> group;
    widget -> screen;

    window -> group;
    window -> screen;
    window -> layout;
}