“do_short” not equal to “echo do_shortcode”

Just to let you know…

I used do_short('[preview_template]'); in a (php) page template to preview content to non-logged in users with an url like example.com/preview/?id=1234. The shortcode outputs te code below.

[pass global=query fields=id] 
	[if pass='{ID}' empty=false] 
	
		[loop status=any id='{ID}']

		[switch type]
	
		[when post][load dir=child file=content-single.php][/when]
		[when page][load dir=child file=content-page.php][/when]
		[when fotoalbum][load dir=child file=content-fotoalbum.php][/when]
		[when sponsor][load dir=child file=content-sponsor.php][/when]
		[when mededeling][load dir=child file=content-mededeling.php][/when]
		[when ai1ec_event]<p>Activiteiten previewen is helaas niet mogelijk...</p>[/when]

		[when default]
		[load dir=child file=content-single.php]
		[/when]
	
		[/switch]
			
		[/loop] 
		
	[else]<p>Er is hier niets...</p>
		
	[/if] 
	[is login]<p><a href="[url site]/wp-admin/post.php?post={ID}&action=edit">Bewerken</a></p>[/is]
[/pass]

When the content of the post contains a YouTube URL to embed a video, the video will show up. Also the [gallery]-shortcode and [gravityform]-shortcode do not work as it has to be.

I resolve this with using echo do_shortcode('[preview_template]'); instead of do_short('[preview_template]');.