In my case it turned out to be a plugin conflict too. The culprit was WP-Polls 2.62 After turning it off and on again, the widget page won’t even load properly…
Same problem here. Nothing works on the widgets page after the update to 3.3. No drag and drop, no Screen Options or Help button, I can’t even access the properties of the installed widgets by clicking on the down arrow! I have tried Firefox, Chrome and Microsoft Explorer. This is very annoying!
The rest of the backend seems to work just fine, just the widgets page is broken.
