I've noticed there is a bug with the grouped list view when using the datasource. When the group is removed the listview reverts to ungrouped but the styling is not updated.
I discovered the fix below... but the framework should handle this automatically.
(Tasks is the DataSource Object)
tasks.group({field: "Importance"});
The grouped listview looks fine. Until...
Group is removed but the list formatting does not revert to the appropriate style.
The following
manual updates need to happen:
$("#ulList").removeClass("km-listgroup");
$("#ulList").addClass("km-list");
Now it looks acceptable.