I have seen a number of threads on this, most closed with no fix. I have tried clearing my cache and cookies.
I upgraded three blogs to 3.2.1. All on the same sever. After upgrade some post editor popup do not work on two of the blogs. For example, on paste popup, two blogs work fine, on the third the popup is empty. For the horizontal bar two work, the third shows code rather than text in the popup.
I have tried several computers, all do the same. The broken blog and one that works are running current Thesis, the other that works is no. One that works and the one that do not have the same plugins.
I have checked plugins, permissions, and files and can find no differences in the blogs that work and those which do not. All three blogs worked the same way before upgrade.