I have a fresh install of SS 2.3.0 on Lighttpd (with the recommended redirect entries). However, when I try to edit content in html I get a screen like the attached. This worked fine in 2.2.3. I saw the problem after upgrading. Since then I re-installed 2.3.0 from scratch and copied my old site over (still a problem) and then installed SS 2.3.0 from scratch with NO additions. Still see the problem.
I am using Safari 3.2.1 on OS/X 10.5.6. No changes to my OS between the changes to SS.