diff --git a/product/ERP5Form/Tool/SelectionTool.py b/product/ERP5Form/Tool/SelectionTool.py
index 506102d88f4f329564f2029b30cd43cb3d83e701..3fc2227cb811701ed228de0976738450664bf2c2 100644
--- a/product/ERP5Form/Tool/SelectionTool.py
+++ b/product/ERP5Form/Tool/SelectionTool.py
@@ -1238,7 +1238,7 @@ class SelectionTool( BaseTool, UniqueObject, SimpleItem ):
 
         proxy_listbox_ids = field.get_value('proxy_listbox_ids')
         REQUEST.set('proxy_listbox_ids', proxy_listbox_ids)
-        if len(proxy_listbox_ids) == 1:
+        if len(proxy_listbox_ids) > 0:
           REQUEST.set('proxy_listbox_id', proxy_listbox_ids[0][0])
         else:
           REQUEST.set('proxy_listbox_id',