Get DockPanel suite tab order

Question

Is there some collection or some other property, where it is possible to get the current order of tabs in the DockPanel Suite? I open several tabs in some order by default and then, after some action, I want to get the current tabs order. The user can change tabs order manually. There is a DockPanel.Contents collection, but the order in this collection is not corresponding with the real tabs order. I was also not able to find some index property, or something like that in the DockContent.
There is this question which tells me, how to show tabs in the specified order, but there is no information about also getting the order.