Manual Tests
See $Window.js comment "Test cases where it should refocus the last focused control in the window" for many manual tests.
In Triggering applet, clicking Focus Now button should focus a window.
Test that menus, submenus, and child windows close, when closing a window (on a delay).
Trigger pointerdown/mousedown then click off the main window quickly, and it should be refocused.
(For click event, I'm not sure but I think it shouldn't focus, because you may want to trigger an action by calling `click()` and that shouldn't refocus; does `click()` generate a bubbling click event though?)
Test that focus is shown on both the tool window and the parent window when focus lies within the tool window.
Test that controls in nested iframes get refocused when refocusing a window. Note that the innermost button is unstyled and may not get a focus ring unless you then use the keyboard.
Tool windows probably shouldn't focus controls automatically on click, they're mainly supposed to keep the parent focused. @TODO?
Clicking title bar button should not show a focus ring, or store it as the last focused control. It should keep focus on whatever was focused before the title bar button was clicked.
Clicking in a window with no focusable controls should focus the window-content itself.