Is it possible to get the screen position for the layout container (which could be the DocumentContentHost) in side the XamDocManager?
What element are you referring to when you say "content holder"? The ContentPresenter within the template of the xamDockManager is positioned by the DockManagerPanel (which also contains the docked splitpanes) so its position is that of the central content.
The reason I am asking is beacuse when I get the screen position for the content holder, if there are panels on the left hand side of the content holder than the X position is wrong. If I close the the left hand side panels than the retrieved X position is valid.
If you're asking how to convert a point to screen coordinates then Visual - the base class of all elements - has a PointToScreen method that you can use to find out the screen coordindates of a point relative to that element. If you're asking about getting to an element that contains the central content then there isn't anything on the xamDockManager to help with that since its lookless but basically it contains a ContentPresenter within its default template that will contain the content whether that be a DocumentContentHost or something else.