PriorityHeaderItems allows parents to move their header items infront of those of their children (parent-first instead of child-first).
But the current implemention sorts PriorityHeaderItems of siblings in reverse order, e.g. having a component hierarchy as follows:
... the PriorityHeaderItems of all these components are sorted as:
Why should the PriorityHeaderItem of component AB be before that of AA? This isn't parent-first, it is reverse-order.
IMHO a more suitable ordering would be "parent-first-preserving-siblings":