core-bundle/src/Resources/contao/dca/tl_page.php
public function makeRedirectPageMandatory(Contao\DataContainer $dc)
	{
		$objPage = $this->Database->prepare("SELECT * FROM " . $dc->table . " WHERE id=?")
								  ->limit(1)
								  ->execute($dc->id);

		if ($objPage->numRows && $objPage->type == 'logout')
		{
			$GLOBALS['TL_DCA']['tl_page']['fields']['jumpTo']['eval']['mandatory'] = true;
		}
	}
public function makeRedirectPageMandatory(Contao\DataContainer $dc)
	{
		$objPage = $this->Database->prepare("SELECT * FROM " . $dc->table . " WHERE id=?")
								  ->limit(1)
								  ->execute($dc->id);

		if ($objPage->numRows && $objPage->type == 'logout')
		{
			$GLOBALS['TL_DCA']['tl_page']['fields']['jumpTo']['eval']['mandatory'] = true;
		}
	}
public function makeRedirectPageMandatory ( Contao \ DataContainer $ dc ) { $ objPage = $ this -> Database -> prepare ( "SELECT * FROM " . $ dc -> table . " WHERE id=?" ) -> limit ( 1 ) -> execute ( $ dc -> id ) ; if ( $ objPage -> numRows && $ objPage -> type == 'logout' ) { $ GLOBALS [ 'TL_DCA' ] [ 'tl_page' ] [ 'fields' ] [ 'jumpTo' ] [ 'eval' ] [ 'mandatory' ] = true ; } }
Make the redirect page mandatory if the page is a logout page

@param Contao\DataContainer $dc

@throws Exception
Make the redirect page mandatory if the page is a logout page