Customizing Popup Window in PRISM5

Jul 11, 2014 at 11:42 PM
From the InteractivityQuickStart sample, I'm trying to customize the PopUp window to make it a ToolWindow (remove controlbox etc.). I was hoping this would do it:
<prism:InteractionRequestTrigger SourceObject="{Binding ConfirmationRequest, Mode=OneWay}"
            <prism:PopupWindowAction IsModal="True" CenterOverAssociatedObject="True" >
                    <DefaultPopupWindows:DefaultConfirmationWindow WindowStyle="ToolWindow"/>
But I get a runtime error: Window must be the root of the tree. Cannot add Window as a child of Visual.

Is it the case one still needs to implement this behavior in PRISM5 such as described here:
Jul 14, 2014 at 8:57 PM
Looks like you are trying to add a new Window instance as the WindowContent of the PopupWindowAction. The PopupWindowAction.WindowContent expects a user control to provide the content of the window.

The actual window is provided by the PopupWindowAction GetWindow virtual method. The CreateDefaultWindow method returns either a confirmation or notification style window based on the notification. I suggest you derive from PopupWindowAction and override the GetWindow method.