Fix #7 issue.

zabbix/queryCtrl.js

@@ -65,7 +65,7 @@ function (angular, _) {
 
     // Call when host selected
     $scope.selectHost = function() {
-
+      if ($scope.target.host) {
         // Update item list
         if ($scope.target.application) {
           $scope.updateItemList($scope.target.host.hostid, $scope.target.application.applicationid);
@@ -75,6 +75,7 @@ function (angular, _) {
 
         // Update application list
         $scope.updateAppList($scope.target.host.hostid);
+      }
 
       $scope.target.errors = validateTarget($scope.target);
       if (!_.isEqual($scope.oldTarget, $scope.target) && _.isEmpty($scope.target.errors)) {