I have no idea why it does not work. Specifically, “space” and “backspace” did not work.
You will generally have better success in getting an answer if your post the relevant specific code, rather than hope that people will download a file and navigate through it to the place where you are having an issue (although posting the .psyexp is always a useful backup to a well-posed question). Also, explain exactly what “did not work” means. This helps people understand your actual issue.