OpenERP tree view

Question

I want to replace one of the defaults buttons in treeview header by one with a funcionality made by my... I try using xpath in this way but not worked

<field name= "types_id" colspan="8" nolabel="1">
                    <tree options='{"deletable": false, "addable":null, "isClarkGable": false}'>
                        <field name="type_id"/>        
                        <field name="fundamentation"/>    
                        <xpath expr="//tree/button[@string='Add']" position="replace">
                            <button name="button_cancel" string="Mark to Cancel" type="object" icon="gtk-cancel"/>
                        </xpath>                    
                    </tree>
                </field>

Answer 1

The option you are using is for field not for the tree tag. so your xml will be like,

<field name= "types_id" colspan="8" nolabel="1" options='{"deletable": false, "addable":null}'>
     <tree delete="false" string='YOUR STRING'>
         <field name="type_id"/>
         <field name="fundamentation"/>
         <xpath expr="//tree/button[@string='Add']" position="replace">
             <button name="button_cancel" string="Mark to Cancel" type="object" icon="gtk-cancel"/>
         </xpath>
     </tree>
</field>