<data priority="50">
    <t t-set="layout_document_title" position="replace">
        <t t-set="layout_document_title">
            <span t-if="is_proforma">Pro-Forma Invoice </span>
            <span t-elif="doc.state in ['draft','sent']">Offer for </span>
            <span t-else="">Order </span>
            <span t-field="doc.name">SO0000</span>
        </t>
    </t>
</data>