feature Control, a "button" control
    action = new GeoExt.Action({
    control: new OpenLayers.Control.WMSGetFeatureInfo({
autoActivate: true,
infoFormat: "application/vnd.ogc.gml",
maxFeatures: 6,
layers: [layers1],
propertyName: "name1,name2,name3",

eventListeners: {
    "getfeatureinfo": function(e) {
        var items = [];
        Ext.each(e.features, function(feature) {

            items.push({
               xtype: "propertygrid",
               title: feature.fid, // here i change it to feature.name1 it doesn't work
                source: feature.attributes

            });
        });
        new GeoExt.Popup({
            title: "infos",
            width: 250,
            height: 300,
            layout: "accordion",
            map: map,
            location: e.xy,
            items: items
        }).show();
      }
    }
   }),
    map: map,
    text: "infos",
    tooltip: "Infos "
      });
    actions["infos"] = action;
    toolbarItems.push(action);
    toolbarItems.push("-");

propertyName: "name1,name2,name3",

vendorParams: {
                propertyName: "name1"
            }