gravity_forms_tabindex.php

<?php

/*
	#########################################################
	---------------------------------------------------------
	-- Fix tabindex in Gravity forms
	---------------------------------------------------------
	#########################################################
*/

/**
 * Prevent the focus to jump outside of a Gravity form upon
 * pressing tab.
 *
 * Install this snippet in your theme's functions.php.
 *
 * This is David Smith's script at: http://gravitywiz.com/
 * fix-gravity-form-tabindex-conflicts/
 * Thank you David for sharing!
 *
 * Last version: https://gist.github.com/31b7e1a2d874dc41d4a6
 */

add_filter( 'gform_tabindex', 'gform_tabindexer', 10, 2 );
function gform_tabindexer( $tab_index, $form = false ) {
    $starting_index = 1000; // if you need a higher tabindex, update this number
    if( $form )
        add_filter( 'gform_tabindex_' . $form['id'], 'gform_tabindexer' );
    return GFCommon::$tab_index >= $starting_index ? GFCommon::$tab_index : $starting_index;
}

?>