WindowTack ensures that when running in windowed mode, the position of the render window is remembered and restored on subsequent runs.
Initially, the render window will be centered on the primary screen. Afterwards, the render window will appear at exactly the same place where it was when you ran Orbiter last. In full-screen mode WindowTack simply does nothing.
WindowTack remembers window position separately for each screen resolution and each window size, and will remember the position even if you manage to crash Orbiter or terminate the process - making it addon developer friendly.