Fix visibility of invoice_print button on invoice form

account_usability/account_view.xml

@@ -41,6 +41,13 @@
         <xpath expr="//field[@name='tax_line_ids']/tree/field[@name='amount']" position="before">
             <field name="base" readonly="1"/>
         </xpath>
+        <!-- Warning: there are 2 invoice_print buttons in the native view... probably a bug -->
+        <xpath expr="//button[@name='invoice_print']" position="attributes">
+            <attribute name="attrs">{'invisible': [('state', 'not in', ('open', 'paid'))]}</attribute>
+        </xpath>
+        <xpath expr="//button[@name='invoice_print'][2]" position="attributes">
+            <attribute name="attrs">{'invisible': True}</attribute>
+        </xpath>
     </field>
 </record>