I know SS2.3 is a bit ancient, but I have a DOM in there (from the branch link in the sticky topic of this forum).
On my live server, it breaks on Firefox (works in Safari). On my local test dev server, it works fine.
As you can see, it also has some weird CSS issues, this also happens in Safari, but ony on the live server:
https://skitch.com/dendeffe/r6ysy/silverstripe-cms-pagina-inhoud
The ony error I get in firebug is in the Net panel:
http://<mydomain.com>/admin/EditForm/field/BannerImages/upload
gives a 404