private void AddCategory(object param)
        {
            AddCategoryModel categoryModel = Controller.GetNewCategoryFromUser(Categories);

            if (categoryModel == null || categoryModel.DialogResult == false)
            {
                return;
            }

            Category category = categoryModel.Category;

            Categories.Add(category);

            SelectedCategory = category;

            //Add category to storage
            _storage.AddCategory(category);
        }