Ever change the resolution of your monitor, plug in another monitor, or play a computer game? If so, you've been a victim of icon/window rearrangement. This is the dreaded side-effect that causes your neatly placed desktop icons and application windows to pile up in a corner.
Desktilty solves the issue by 'locking' the icon and window positions. Whenever they move, Desktility can automatically put them right back for you, instantly.