How to know which window become floating in FloatingWindowOpening event

private void DockSite_FloatingWindowOpening(object? sender, FloatingWindowOpeningEventArgs e)
        {
            IEnumerable<DockingWindow>? floatingWindows;
            if (e.DockHostChild is Workspace workspace
                && workspace.Content is TabbedMdiHost tabbedMdiHost
                && tabbedMdiHost.Child is TabbedMdiContainer tabbedMdiContainer)
            {
                // DocumentWindow
                floatingWindows = tabbedMdiContainer.Windows.Where(x => x.IsFloating);
            }
            else if (e.DockHostChild is ToolWindowContainer toolWindowContainer)
            {
                // ToolWindow
                floatingWindows = toolWindowContainer.Windows.Where(x => x.IsFloating);
            }
            else
            {
            }
        }