WPF: Dialog shows *under* the main window. How to get it to rise to the top?

Question

I use this code to produce a print-preview window.

using (XpsDocument doc = new XpsDocument(fileName, FileAccess.Read))
{
    FixedDocumentSequence fds = doc.GetFixedDocumentSequence();

    using (var reader = new System.Xml.XmlTextReader(new StringReader(xaml)))
    {
        Window preview = System.Windows.Markup.XamlReader.Load(reader) as Window;

        DocumentViewer dv1 = LogicalTreeHelper.FindLogicalNode(preview, "dv1") as DocumentViewer;
        dv1.Document = fds as IDocumentPaginatorSource;
        dv1.FitToMaxPagesAcross(1);

        // show the dialog
        preview.ShowDialog();
    }
}

But the preview window typically shows beneath the main Window. How can I get the preview to remain on top?

This code dynamically generates a Window from a simple XAML template at runtime, but that particular aspect of the code shouldn't be relevant to the problem I'm having.

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Duplicate:
How do I focus a modal WPF Window when the main application window is clicked?

Answer 1

Set the Owner property of the preview window to the current window before showing the dialog.

preview.Owner = // the current window
preview.ShowDialog();