This is an essential and VERY easy to implement feature: just grab whatever feature is wanted from the currently selected item and traverse the tree. Done.
While we are at it: Another hard to miss feature: Select a bunch of objects, click one of them to designate as the reference object, then do whatever alignment on them.
And no, to use a dropdown menu to select first/last is just not cutting it. Again, rather easy to implement.
Before adding more complex features, Serif should rather focus on usability. Because without the latter, the former don't matter.