Similar Problem - IE9 appears to be culprit
Hi
I too have experienced exactly this type of problem. I have completely reinstalled V2.1.0 from scratch with a new database, different server and still the same problem. Then I remembered I had installed IE9 RC in the last couple of days, seemed to be working fine with Dreamweaver so did not suspect at first. Desperation set in so I tried Chrome and then all of a sudden the editor burst into glorious life. If you experience this, check you're not using IE9 RC