Lines must not be obligatory, because sometimes, we want to display empty matrixbox.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@2745 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Form/MatrixBox.py

@@ -89,7 +89,7 @@ class MatrixBoxWidget(Widget.Widget):
       couple[0] is the variation, and couple[1] is the name displayed to the user.
       For example (('size/baby/02','baby/02'),('size/baby/03','baby/03')), Required"""),
                                  default=[],
-                                 required=1)
+                                 required=0)
 
     tabs = fields.ListTextAreaField('tabs',
                                  title="Tabs",