How do you move items that are children to the same level as their parents?

I can drag items at the same level to somewhere else at the same level, and I can drag children from one parent to another, but I can't drag a child to the same level as its parent (ie. promote it to be a top level page instead of a second level page).

Is this a bug in drag/drop or a "feature" of the way c5 manages parent/child pages?

If the later, is it fixable at a lower level? (eg. by writing directly to the DB?)

thanks!
Nathan
PS: Have tried from both the sitemap and the edit page->move/delete sitemap