Most Every Newer Features Being Added Are Being Added For A Single Instance Of A WPF View. It Would Be A Nice Feature / Add-On If Instead A List / Array Of Items Could Be Passed Into the Parameter(s).
Case In Point, I Have An Application I Am Refactoring, And The Refactor Calls For The Ability To Split (GridSplitter, etc) Two Panes, Be Able To Simultaneously Scroll Both Panes, Be Able To Simultaneously Print Both Panes (On One Page Side-By-Side & Line-By-Line), and Be Able To Simultaneously Search Both Panes.
Search & Print For The Most Part Already Exists For AvalonEdit TextView; But Not For Two Panes Simultaneously. I Am Having A Hard Time Tying Two TextView Together To Scroll, Search, & Print Together. This Is A Very Challenging Issue. If This Functionality Was In Your AvalonEdit And/Or AvalonDock Then You Possibly Would Hold A Huge Advantage Over "Competitors".
Just Some Food For Thought...