code/Extensions/CampaignAdminExtension.php
public function updatePopoverActions(&$actions, $record)
    {
        if ($record && $record->canPublish()) {
            $action = FormAction::create(
                'addtocampaign',
                _t('SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ADDTOCAMPAIGN', 'Add to campaign')
            )->setIcon('page-multiple');
            array_unshift($actions, $action);
        }
    }
public function updatePopoverActions(&$actions, $record)
    {
        if ($record && $record->canPublish()) {
            $action = FormAction::create(
                'addtocampaign',
                _t('SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ADDTOCAMPAIGN', 'Add to campaign')
            )->setIcon('page-multiple');
            array_unshift($actions, $action);
        }
    }
public function updatePopoverActions ( & $ actions , $ record ) { if ( $ record && $ record -> canPublish ( ) ) { $ action = FormAction :: create ( 'addtocampaign' , _t ( 'SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ADDTOCAMPAIGN' , 'Add to campaign' ) ) -> setIcon ( 'page-multiple' ) ; array_unshift ( $ actions , $ action ) ; } }
Update the Popover menu of `FileFormFactory` with the "Add to campaign" button.

@param array $actions
@param File $record
Update the Popover menu of FileFormFactory with the Add to campaign button .