1. No window should ever take focus. It should only be possible to throw focus *to* another (possibly newly-opened) window.
2. When a new window appears, it should appear immediately behind the focused window (even if the focused window isn't frontmost). If no window is focused, the new window should open frontmost and focused.
3. When a launcher (or main menu item) is chosen, focus should be removed from all windows (and given to «nothing»).
This last rule means that if the user launches an application *and* doesn't throw focus to any existing window, the new window will appear frontmost and focused.
An amendment to the second rule might be that: if multiple new windows are opened while one window remains focused, the new windows should stack behind the focused window, such that the newest window is always added to the back of the stack.
In my opinion the behaviour should be this:
1. No window should ever take focus. It should only be possible to throw focus *to* another (possibly newly-opened) window.
2. When a new window appears, it should appear immediately behind the focused window (even if the focused window isn't frontmost). If no window is focused, the new window should open frontmost and focused.
3. When a launcher (or main menu item) is chosen, focus should be removed from all windows (and given to «nothing»).
This last rule means that if the user launches an application *and* doesn't throw focus to any existing window, the new window will appear frontmost and focused.
An amendment to the second rule might be that: if multiple new windows are opened while one window remains focused, the new windows should stack behind the focused window, such that the newest window is always added to the back of the stack.