Would this ever be considered?
This has been raised by a few clients I've engaged with so far.
In a large grid type view with lots of DBR references with picklists etc. it means that a user could open up a large number of drop downs all over the page.
Whilst i concede that they can just click on the item to close it again, I think this comes from the fact that, in virtually all cases, drop down items close when another is expanded on nearly every website they've ever visited.