The object my be either a widget or a canvas item. In addition, there must be a well-defined order among the components. Instead, the auxiliary library resorts to defining an arbitrary sequence. The application root window is the first widget in the sequence. Child widgets follow their parents, in stacking order.
Canvas items follow the canvas, in order of creation.
They precede any child widgets of the canvas. Bindings for all widgets are disregarded in this test, since otherwise every widget would appear to accept the focus, owing to the binding of the F10 key. No widget receives the focus if it is not mapped. If a widget is destroyed while it owns the focus, focus is also redirected. The sequence of objects that receive focus is circular.