If Scratch is not in Turbo Mode then the project will force you to switch to Turbo Mode before it continues. ( <Shift> key and Green Flag for Turbo mode ) Q. Why doesn't the project draw to the stage edges? "See inside" the project to see if you can figure it out before reading the answer. A. The Scratch Cat pen draws at the centre of the Scratch Cat costume, but the "if on edge bounce" block bounces the sprite when the edges of the Scratch Cat costume hit the edges of the stage. If we wanted to draw to the edge of the stage, we should just use an empty costume or a tiny 1x1 pixel costume for our pen sprite.
* See this tutorial all about Turbo Mode and detecting if a project is running in Turbo Mode: https://scratch.mit.edu/discuss/post/3680379/ The tutorial also covers "run without screen refresh" custom blocks and good structure for 30 frame per second games. - You can backpack the sprite that forces projects to start in Turbo Mode into your own projects. (no credit required)
