This may or may not be a factor in what you’re seeing, but I thought I’d relate my experience anyway just in case it’s what’s happening to you.
About a year and a half ago I moved a domain from another host to DH. After changing the nameserver info, for about a day and a half the site would sometimes resolve to DH but sometimes would resolve to my old host. It turns out that my ISP’s DNS servers weren’t in sync–one didn’t update to the new info for a day or so after the other one did. So in that case it was purely an issue with my ISP and waiting for things to propagate.
I just tried your site and it came up for me–if you’re still not seeing it, just give it a little more time.
BTW, I think the active domain thing is supposed to have to do with which domain you’re managing at the moment–but I never change it and it’s never caused me any problems managing things in the panel.