[imp] Disabling zip preview

[SSRI]

>> We have to tried to disable Zip file preview by using the inline
>> parameter in both config/mime_drivers.local.php and
>> imp/config/mime_drivers.local.php :
>>
>> 'zip' => array(
>>         'inline' => false,
>>
>> However, previewing zip files still works.
>
> As expected.  'inline' has to do with inline rendering of the ZIP  
> file itself.  There is no practical way of viewing zip data on a  
> browser at this time, so 'inline' doesn't actually do anything (you  
> can actually set to true and nothing will change).
>
> The "preview" of the zip file - better described as a listing of the  
> ZIP contents - is not rendering the ZIP data directly.  Thus the  
> 'inline' option has no effect on this view.
>
> A better example is images.  If you set 'inline' => true, all images  
> will be directly displayed at full size within the message page.  If  
> 'inline' => false, you will only see a thumbnail of the image.
>

Ok.

>> The only way to disable it was to set :
>>
>> 'zip' => array(
>>         'disable' => true,
>>
>> in both config/mime_drivers.local.php and imp/config/mime_drivers.local.php
>>

Why do you have to set disable to true in both files while it is said  
in config/mime_drivers.php that "Individual Horde applications can  
override these settings in their config/mime_drivers.php files" ?