private void ConditionEditor_ConditionRemove(object sender, EventArgs e)
 {
     if (ConditionEditors.Count > 1)
     {
         ConditionEditors.Remove((QueryConditionEditor)sender);
     }
 }
 private void ConditionEditor_ConditionAdd(object sender, EventArgs e)
 {
     ConditionEditors.Add(CreateConditionEditor());
 }