Unfortunately it doesn’t seem to work. Whether it’s checked or not I still can’t move the sprite any further than the canvas borders.
Is there a way around that problem? (Preferably without extending the canvas outside the screen as I’m then saving the image on my device and would like to keep only the part of the canvas I can see on my screen)
That property is not for moving sprites outside a canvas. It’s for detecting moves (dragging) that start inside the canvas and move outside of it.
To simulate moving sprites outside the canvas, make the canvas bigger than the screen. That way the sprite will keep being inside the canvas but outside of the view window.
In that case I would put the canvas inside an arrangement. Make the arrangement the size of the screen (or any size you need the image to be) and the canvas bigger. Then when saving the image, use this extension to save the arrangement, not the canvas.