In most Mac applications it is possible to switch between the open windows of an application using the cmd ~ key shortcut.
I want this in my app too, but I really don't see how to implement.
Most key shortcuts are implemented by adding a shortcut to one of the menu items. But for this one a menu item is not applicable.
In the Keyboard preferences pane, under the Shortcuts pane, Command-` is a system-level keyboard shortcut in the Keyboard category (labeled "Move focus to next window").