The "Bound To Layout" behavior acts something like this:
Set X to clamp(Sprite.X, 0, LayoutWidth)
Set Y to clamp(Sprite.Y, 0, LayoutHeight)
The clamp function will take the Sprite's X and Y positions and will limit them between 0 to layout's width and height, respectively. Changing the last two parts of those clamp functions will change the limits.