diff -r f80aa497b4d7 -r 2be886bff11b src/pyams_portal/zmi/layout.py
--- a/src/pyams_portal/zmi/layout.py	Fri Apr 27 17:41:14 2018 +0200
+++ b/src/pyams_portal/zmi/layout.py	Fri Apr 27 17:49:28 2018 +0200
@@ -228,7 +228,7 @@
 
     def updateWidgets(self, prefix=None):
         super(PortalTemplateSlotAddForm, self).updateWidgets()
-        self.widgets['row_id'].value = self.request.params.get('{0}row_id'.format(self.prefix))
+        self.widgets['row_id'].value = self.request.params.get('{0}{1}row_id'.format(self.prefix, self.widgets.prefix))
         if self.widgets['row_id'].value:
             self.widgets['row_id'].mode = HIDDEN_MODE