i want to open a window view, but without closing the current window, but this code close the curren window, someone help me ?

def button_article(self, cr, uid, ids, context=None):
      ctx = (context or {}).copy()
      ctx['article'] = self.browse(cr, uid, ids[0], context=context).product_id.id
      ctx['form_view_ref'] = 'itk_entrepot.itk_entrepot_article_maj'
      if ctx['article'] :
          return {
        'name':'Article',
        'view_type':'form',
        'view_mode':'form',
        'res_model':'product.product',
        'view_id':False,
        'target':'new',
        'type':'ir.actions.act_window',
        'domain':[('id','=',ctx['article'])],
        'context':ctx,
        'nodestroy':True,
        'res_id':ctx['article'],
            }
      else : return True

<button name="button_article"    string="Article" type="object" class="oe_highlight" icon="article" />

Or who know wwhich function called when we click on the button which appears in the right of the many2one fields ?