I have the same problem here in Firefox 2.0.1 and neither a forced refresh nor a deleting the cache resolved it.
I always only get the two tabs “Visual” and “Code” and for a blink of an eye it seems the editor itself wants to come up, but then the buttons (Save, Publish, …) jump up right underneath the tabs of the editor (while being right-aligned though). I remember having similar problems with 2.0.x and I blamed one of the Firefox Extensions for it.
Now maybe I will try disabling them one in a row… but tomorrow. 🙂
