diff --git a/addons/account_voucher/account_voucher_pay_invoice.xml b/addons/account_voucher/account_voucher_pay_invoice.xml
index da669ad04ee..8703abad9e2 100644
--- a/addons/account_voucher/account_voucher_pay_invoice.xml
+++ b/addons/account_voucher/account_voucher_pay_invoice.xml
@@ -8,7 +8,7 @@
            <field name="inherit_id" ref="account.invoice_form"/>
            <field name="arch" type="xml">
            <button name="invoice_open" position="after">
-               <button name="invoice_pay_customer" type="object" string="Register Payment" states="open" icon="gtk-go-forward"/>
+               <button name="invoice_pay_customer" type="object" string="Register Payment" states="open" attrs="{'invisible':[('sent','=',True)]}" class="oe_form_button_hi"/>
            </button>
            </field>
         </record>