Animation Shop question

In Animation Shop, a lot of the time all I want to do is resize the canvas to add another animation to a current animation, IE, add blinkie boxes to pixels. I know how to resize the canvas in PSP, but when I try to update the changes to AS, the image usually ends up being off center, and cuts out half of it. Any idea how to stop the off centered update, or just resize the canvas to be larger while still in AS? Thanks.