Just a note that drag and drop of widgets does NOT work well with the combination of FrameMarket, GridMarket and MarketPress.
I had to add the global site search and simply could not drag and drop it onto the sidebar.
Some of the widgets would drag - but most not (nothing past the first line of them usually).
After searching I finally found a post from someone else that had the problem and they had to use FireFox to fix it.
FireFox does work as expected, but so should IE9 IMHO.
So this is just an FYI that it is broken there.
If you can't fix it, maybe you should put a note in the docs to use FF so that people don't waste a lot of time or get frustrated at not being able to use it properly.