widget.php

// ...
// nilai default bila $instance['title'] belum diset / kosong (empty)
$title = ! empty( $instance['title'] ) ? $instance['title'] : esc_html__( 'New title' );
?>
<p>
<label for="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>"><?php esc_attr_e( 'Title:' ); ?></label> 
<input class="widefat" id="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>" 
	name="<?php echo esc_attr( $this->get_field_name( 'title' ) ); ?>" 
	type="text" value="<?php echo esc_attr( $title ); ?>">
</p>
<?php
// ...