OwnerCanCloseWithDialog

MyCustomDialog.cs

...
            var settings = new MetroDialogSettings { OwnerCanCloseWithDialog = true };

            var dataContext = new AdvancedInstallViewModel(_chocolateyService.GetAvailableVersionsForPackageIdAsync(Id), Version);

            customDialog.Content = new AdvancedChocolateyDialog { DataContext = dataContext };

            await _dialogCoordinator.ShowMetroDialogAsync(this, customDialog, settings);

            var result = await dataContext.WaitForClosingAsync();

            await _dialogCoordinator.HideMetroDialogAsync(this, customDialog, settings);
...