In previous builds, the DataSet had a property on them that said whether they should clear the DataSet whenever it is Filled by a DataAdapter. It seems to be missing in the latest builds. I actually prefer this because the nature of DataSets (and often overlooked) is that successive DataAdapter.Fill's will allow a DataSet to grow incrementally. New rows will be added, and existing rows will be updated (unless it is dirty, then you would get an exception).
Maybe my ranting to Steve Lasker paid off in a small way.
The original LadyBug on this is here if you have an opinion and want to vote to have it changed. I've reopened it to figure out what they've done with it.
UPDATE: Steve Lasker correctly pointed out that it is on the TableAdapter (d'oh), but not in the designer for some reason. I am going to update the LadyBug to complain about the designer issue.