=== modified file 'sale/stock.py'
--- sale/stock.py	2010-03-23 10:19:47 +0000
+++ sale/stock.py	2010-07-06 06:48:43 +0000
@@ -35,7 +35,7 @@
 class stock_picking(osv.osv):
     _inherit = 'stock.picking'
     _columns = {
-        'sale_id': fields.many2one('sale.order', 'Sale Order', ondelete='set null', select=True, readonly=True),
+        'sale_id': fields.many2one('sale.order', 'Sale Order', ondelete='set null', select=True),
     }
     _defaults = {
         'sale_id': lambda *a: False

=== modified file 'stock/stock_view.xml'
--- stock/stock_view.xml	2010-03-17 12:50:27 +0000
+++ stock/stock_view.xml	2010-07-06 06:50:42 +0000
@@ -872,7 +872,7 @@
                         <page string="Others info" groups="base.group_extended">
                             <field name="active" select="2"/>
                             <field name="auto_picking"/>
-                            <newline/>
+                            <field name="sale_id"/>
                             <field name="date" select="2"/>
                             <field name="date_done" select="2"/>
                             <field name="move_type"/>