I don't know of any application specific drag/drop tweaks in Win 7, the only one I know of is
Right Click Start Button,
Start Menu Tab,
Customise Button, (the list is alphabetical order)
Enable context menus and dragging and dropping
It should be checked, uncheck and see what happens, then check and try again - I saw this suggested for a drag drop problem in XP - it fixed the problem, so the OP said.