private void BtnCover_OnClick(object sender, RoutedEventArgs e) { var win = SubWindow.Create("Cover Dialog"); win.Show(WindowZOrder.Top); var coverWin = new CoverWindow { Owner = win, Top = win.Top, Left = win.Left, Background = Brushes.Black, Title = "CoverWindow" + SubWindow.GetOrder("Cover Dialog") }; WindowsDockManager.SetDockBehavior(coverWin, new DockBehavior { Dock = WinPosDockFlag.Full, RegionName = "CoverRegion", IsDockKeep = true }); coverWin.SetDockOwner(win); coverWin.Show(); coverWin.Hide(); var coverWin1 = new CoverWindow { Owner = win, Top = win.Top, Left = win.Left, Background = Brushes.Gray, Title = "CoverWindow" + SubWindow.GetOrder("Cover Dialog") + "_1" }; WindowsDockManager.SetDockBehavior(coverWin1, new DockBehavior { Dock = WinPosDockFlag.Full, RegionName = "CoverRegion", IsDockKeep = true }); coverWin1.SetDockOwner(win); coverWin1.Show(); ShowMemorySize(); }