The sorry reply late.

If set a value to the hidden field using the autocomplete, it is empty value to post if do not set a value.
Therefore pass through the isset() check.
```php
if (!isset($args[$field['field']])) {
    continue;
}
```
If this change the if(empty()),the search criteria "false" or "0" can not be specified if the "type = value".

ex)
```html
<input type="hidden" name="data[Article][blog_id]" value="" />
<input type="text" name="data[Article][blog_input]" value="" />
```
```php
debug($this->request->data);

array(
    'Article' => array(
        'blog_id' => '',
        'blog_input' => '',
    )
)
```