[giow] (0) Make the viewport around a <dialog> always scrollable. Don't ask me what happens if an unscrollable viewport is scrolled while a dialog is up and then the dialog goes away, that isn't clear at this time. If you think we should scroll back to the previous position, or force a previous dialog to be visible, or some such, file a bug with details, please. Thanks...
Affected topics: CSS, HTML

git-svn-id: http://svn.whatwg.org/webapps@8363 340c8d12-0b0e-0410-8428-c7bf67bfef74