关于Purchase Supplied Goods模块

[qq342406169]

[quote]
本模块将限制用户在开采购订单时只能选择由该供应商供货的产品。

产品选择列表中将只列示： 1. 产品的供应商列表中包含采购订单上所选择的供应商的产品； 2. 产品的供应商列表为空的产品
[/quote]
这是Purchase Supplied Goods的功能描述，但我安装后发现只能显示第1点功能，而第2点是没有显示的，查看了代码，如下：

<br />&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;<br />&lt;openerp&gt;<br />&nbsp; &nbsp; &lt;data&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &lt;record id=&quot;purchase_supplied_goods_form&quot; model=&quot;ir.ui.view&quot;&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;field name=&quot;name&quot;&gt;purchase.supplied.goods.form&lt;/field&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;field name=&quot;model&quot;&gt;purchase.order&lt;/field&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;field name=&quot;inherit_id&quot; ref=&quot;purchase.purchase_order_form&quot;/&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;field name=&quot;arch&quot; type=&quot;xml&quot;&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;xpath expr=&quot;//field[@name=&#039;product_id&#039;]&quot; position=&quot;attributes&quot;&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;attribute name=&quot;domain&quot;&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [(&#039;product_tmpl_id.seller_ids.name.id&#039;, &#039;=&#039;, parent.partner_id)]<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;/attribute&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;/xpath&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;/field&gt;<br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;/record&gt;<br />&nbsp; &nbsp; &lt;/data&gt;<br />&lt;/openerp&gt;<br />

product_id的domain为parent.partner_id，要显示产品的供应商列表为空的产品，应该要增加一个or条件，请问怎样判断product_tmpl_id.seller_ids为空呢？？？