Problems getting the editor to display aerial imagery

I have the exact same problem. None of the basemaps show up in the editors, though they're fine in the view tab. I've raised the issue with our NMC people but as far as I know you're the first to have reproduced the issue. I'm using Firefox as well but the problem shows up in Chrome and Opera too, at least under Linux. I've done some debugging and I think the problem is that modern browsers are unhappy with "mixed content" meaning mixing https:// traffic with http:// traffic. The editors themselves are accessed via an https URL, but the tiles are loading from http sources, and browsers don't like that because it's a security risk. This problem only cropped up for me in the last 3-4 weeks.

Our developer has taken steps that hopefully will resolve the "mixed content" issue. Please let us know if you are having any better luck with the editor base layers now. Thanks!