After using repl.it for a while recently (BTW great product overall, congratulations), I've found a rather annoying lack of editor tabs. Yeah, you can go to the file menu and click on a file to open it, but if you have lots of files it's
inconvenient. Instead, right above the main textbox that contains your code, there should be a few tabs that you can click on to jump to editing that file. Opening a file through the file menu should jump to that file's tab (if it was already opened), or create a new tab (if it wasn't opened). You should be able to close tabs, too.