So the site was working all fine. i created some maps. After few maps it kinda "got stuck" so i refreshed the page. Now im sitting and watching the base color with nothing in it. All buttons dissappeared etc :(
Probably IE wasn't really restarted, one of his processes is hanging there and it's corrupted (at least it happens to Chrome from time to time). Right now I can't tell you how to resolve it, but you can try the non-itch version of the generator.
I had the same problem with Chrome. When I tried Microsoft Edge it worked, however after trying Edge again after closing it I got the same result as with Chrome and it wont work again. I have restarted the computer but none of them work atm.