Since I was having issues with upgrading to 2.4.0, I made a fresh new install and all worked well. Pointed installation to my existing database and all was working well... for a while. Now when I click on a page in the CMS, the content area comes up all html. The icons in the CMS editing area are gone. The little circle on the page name just goes round and round. Any ideas?
Try flushing your CMS - http://<yoursite>/admin/?flush=1.
This worked for me! :-)
Thanks for your reply. I did try that many times - I had quite a pickle with version 2.4.0, even after I reverted back to 2.3.7. I finally just made a brand new installation (again) of 2.4.0 and brought my pages back into the new database. Apparently some of the modules I had installed (but wasn't actually using, thankfully) didn't play well with the new version. It's working now, but I'm not sure I'm going to upgrade my second silverstripe site right away. Thanks again.
Had the same symptoms on a wamp version of 2.4 which had me stumped since it didn't happen with the live version of the site.
Thanks to figjam for the suggestion of appending ?flush=1 onto the admin url - all is back to normal after this.