2 ways to turn the background to grey: Up arrow, Green flag If you want to stop, here are the 3 ways: (CODE EDITOR ONLY) The [ broadcast (Stop) ] block, Press the button on the top-left of the stage, Press [space] on your keyboard
That size hack was from many Scratch YouTubers, including SL SMART MIND on YouTube, also known as @rehanscratch (https://scratch.mit.edu/users/rehanscratch/)