thats a preposterous idea, but i wanna be able to edit the level while i play it
kinda like super mario bros x (cool fangame by redigit), where you can add (some) stuff while playtesting the level, and once you go back to the editor, the changes wouldnt be made. i kinda liked this so i wish it was here too (and also because its somewhat weird to switch between playtest and editor).
maybe make f5 the mode switcher? (editor -> playtest and reverse)