In Project Overview, Milestones appear in order by
- First, those without a Due date in the order of appearance in the unsorted project List view from top to bottom, and
- Second, those with a Due date, in ascending Due date order
You can’t change those rules, but you can affect a Milestone’s position in the list by its having a Due date or not, and if no Due date, by shifting it up/down in the unsorted project List view.
Hope that helps,
Larry