Sometimes you might want to create a custom page template that is built entirely using widgets. This can give your content a lot of flexibility for the end user; however, it could also be confusing. If you're not using the standard WordPress editor at all in your template, you should disable it and explain why it has been removed. This code will…

wordpress-widgeted-page-template-helper.php

<?php
/**
* If your theme or plugin has a page template that
* uses widgets to build the layout, users might be
* confused as to why the standard editor doesn't
* work as expected. This will disable the editor
* and introduce a notice explaining its absence.
*
* @author     FAT Media <http://youneedfat.com>
* @copyright  Copyright (c) 2013, FAT Media, LLC
* @license    GPL-2.0+
*/

/**
 * Perform a check to see whether or not a
 * widgeted page template is being used.
 *
 * @todo    Replace prefix with theme or plugin name
 * @return  bool
 */
function prefix_using_widgeted_template() {
	// Store all the widgeted templates
	$widgeted_templates = array( 'your-template.php' );

	foreach ( $widgeted_templates as $template ) {
		// Return true for all widgeted templates
		if ( get_page_template_slug( $_REQUEST['post'] ) === $template )
			return true;
	}
	// Return false for other templates.
	return false;
}

add_action( 'admin_init', 'prefix_remove_widgeted_editor' );
/**
 * Check to make sure a widgeted page template is
 * selected and then disable the default WordPress editor.
 *
 * @todo  Replace prefix with theme or plugin name
 */
function prefix_remove_widgeted_editor() {
	// Return early if a widgeted template isn't selected.
	if ( ! prefix_using_widgeted_template() )
		return;
	// Disable the standard WordPress editor.
	remove_post_type_support( 'page', 'editor' );
}

add_action( 'admin_notices', 'prefix_widgeted_admin_notice' );
/**
 * Check to make sure a widgeted page template is
 * selected and then show a notice about the editor
 * being disabled.
 *
 * @todo  Replace prefix with theme or plugin name
 * @todo  Replace 'text-domain' with theme or plugin text domain
 */
function prefix_widgeted_admin_notice() {
	// Return early if a widgeted template isn't selected.
	if ( ! prefix_using_widgeted_template() )
		return;
	// Display a notice to users about the widgeted template.
	echo '<div class="updated"><p>';
		printf (
			__( 'The normal editor is disabled because you\'re using a widgeted page template. You need to <a href="%s">use widgets</a> to edit this page.', 'text-domain' ),
			'widgets.php'
		);
	echo '</p></div>';
}