Thanks Plinkie, that seems to have sorted that issue, but something similar seems to be happening when I add the logic back.
The yellow box (Sprite), should align to the right edge of AdvanceRope, then its width should be set to the ScreenWidth - (Sprite.X+59), which is the distance between the edge of advance rope and the screen, and so the whole area is filled. Yet, when I set the width, Sprite spawns in the middle of the gap, and then that forumla above sets the width to nearly 0.25 of the screen. Do you have any ideas?
Event sheet: imgur.com/mrhPbzi