field Subscription of 'optical_equipment.equipment' always readonly

view/optical_equipment_form.xml

@@ -2,7 +2,6 @@
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
      this repository contains the full copyright notices and license terms. -->
 <form>
-    <field name="subscription_history"/>
     <label name="company"/>
     <field name="company"/>
     <label name="location"/>
@@ -39,4 +38,11 @@
     <field name="health_register"/>
     <label name="origin_country"/>
     <field name="origin_country"/>
+    
+    <notebook>
+	<page string="Subscriptions" id="subscriptions_equipment">
+	    <field name="subscription_history"/>
+	</page>
+    </notebook>
+
 </form>