Editing published code in IDE

I have several apps that I’ve published that were provided by others. I did this by creating a new Smartapp, clicking on the “From Code” tab, pasting in the raw code from GitHub, saving and publishing. Now I’d like to modify one of them but I can’t figure out how to edit it. On a previous one, I ended up deleting it then re-publishing using the modified code but shouldn’t I be able to do that by editing what’s there?

I’m a newbie at this so it’s quite possible that I’ve overlooked something basic.

Thanks.

I found out what the problem was - I was using Microsoft EDGE and the existing code did not appear. When I switched to IE, it appeared as expected.