In searchtool, user widget is used as string : ok
In contenttool, user widget is used as user but returns string : fail (can not save)

I think, that the userwidget should not handle string, and searchtool should handle user..

Plus, there is another problem : if the populations contains more than 50 users, not all are displayed, and if I try to set a value that is not among those 50, the widget fails to set this value, because the store of Ext.form.field.Tag do not find the value in its store