I am 99% sure this does not exists and if it does not than this will quickly turn into an enhancement request. (or maybe I am looking at this all wrong) So I am aware of the DockSite.AreDocumentWindowsDestroyedOnClose property. This is an “all or nothing” approach, meaning all documents are destroyed or not destroyed. What about a situation where I need some documents of a specific type to be destroyed and other documents of a different type to just be hidden so it can be shown/opened later (like a ToolWinow)? I realize that I might be thinking about what should be a document vs. a tool window incorrectly, but without getting to that argument I just wanted to see if it was possible. My suggestion would be making it possible to bind a delegate to the DockSite (because we are MVVM) that would accept the Type of the DataContext of the DocumentWindow that is being closed and return a Boolean where true means destroy it and false means just hide it like a ToolWindow….or have something in the ViewModel that can be asked should it be destroyed or just hidden. It’s just a thought.