With Exit Bosskey you can hide a window for use later in a flash by pressing enter while holding the shift key. If you have a small monitor you can keep clutter safely hidden away. At any time you can restore a hidden window by pressing shift-enter again. Exit Bosskey runs in the tray so it doesn't create any more annoying windows. After all, the point is to reduce the amount of windows open.
Do not open multiple instances of Exit Bosskey, this can cause unpredictable behavior.
When Exit Bosskey closes it restores the hidden window so users don't lose their window forever. Wait for the next version of Exit Bosskey to have even better window loss protection, multiple window support, and to enable changing of the hot key.