Linq to Objects: does GroupBy preserve order of elements?

Question

Does Enumerable.GroupBy from LINQ to Objects preserve order of elements in the groups?

Answer 1

Found answer on MSDN: Yes.

The IGrouping<TKey, TElement> objects are yielded in an order based on the order of the elements in source that produced the first key of each IGrouping<TKey, TElement>. Elements in a grouping are yielded in the order they appear in source.