Window Context

When actions are triggered by mouse or keyboard events, or menu actions from menus originally popped up by mouse or keyboard events, a context window is saved, which is used as the default for window operations that are not passed their optional window argument. This allows the user to easily bind actions to events without worrying about passing around the window argument. However, it is unclear whether behind-the-scenes magic like this is a good idea. The merit of this approach is still under consideration; it may be changed entirely.