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/**
 * Gravity Wiz // Gravity Forms // Hide Fields Hidden via CSS Classes from {all_fields} Merge Tag
 * http://gravitywiz.com/
 */
add_filter( 'gform_merge_tag_filter', function( $value, $merge_tag, $modifier, $field ) {

	if ( $merge_tag == 'all_fields' && $modifier == 'nohidden' ) {
		$css_classes = explode( ' ', $field->cssClass );
		$matching_classes = array_intersect( array( 'gf_hidden', 'gf_invisible' ), $css_classes );
		if( ! empty( $matching_classes ) ) {
			return false;
		}
	}

	return $value;
}, 10, 4 );