Dialogs, Menus, etc.

- Test dialogs, menus, and other things that "pop" open.

Focus is set to the dialog when it appears.
You can navigate forward and backward with the keyboard within the dialog.
Modal dialogs (those that require user action) maintain keyboard focus until dismissed.
Non-modal dialogs (those that do not require user action) close when focus leaves the dialog.
If a visible "close" button is present, it is keyboard-accessible and properly labeled.
Pressing Esc closes the open content.
When it closes, focus returns to a logical place.