It has nothing todo withnthe olugins. The problem occurs after upgrading to wp 3.1 Same problem here on RT-Theme 9.
I even did a clean install with a new database and no PLUGINS at all. The same problem occurs and the widgets are frozen. You can not move them anymore or drag and drop them.
You can not drag and drop the widgets anymore. In no browser at all.
This is really frustrating.
I just copied 3.05 back over 3.1 and wp ask me to update the database again. I did this and now every thing is working in 3.05
But i can not for see if this downgrade gives me any future problems when upgrading again