V9: which asset provides date picker?

Developing with Concrete
5

Ran into this issue today also. The built in form block still tries to use the jQuery UI datepicker if you have a date/time field, which is broken unless your theme pulls in all of core/cms or you manually add jQuery UI to your theme. My fix in page_theme.php registerAssets():

$al = \Concrete\Core\Asset\AssetList::getInstance();
$al->register('css', 'jquery/ui', 'css/jquery-ui.css');
$al->register('javascript', 'jquery/ui', 'https://code.jquery.com/ui/1.13.2/jquery-ui.min.js', ['local' => false]);
$al->registerGroup('jquery/ui', [
    ['javascript', 'jquery/ui'],
    ['css', 'jquery/ui']
]);
$this->requireAsset('jquery/ui');