Theme Preview using "Customize.php" error

[selnomeria]

Hello.
Whenever my homepage is set to be 301 redirected to i.e. mysite.com/somepage, then when Under Appearence(in Dashboard), i click "Customize", then on the right side of the preview window,it doesnt show anything. It is blank.
see preview - ​http://i.imgur.com/6c00M2f.png

[selnomeria]

As i see, that the first time, the customize.php is loaded, and after that, the website php is loaded separately, then I am forced to use this trick in my theme's functions.php, to avoid that problem(because cookies are read on the next execution of the page):

if (strpos($_SERVER['REQUEST_URI'], '/wp-admin/customize.php?return=') !== false)	{setcookie('my_Redirect', 'disable', time()+100000000, '/');}
else	                                                                                {setcookie('my_Redirect', 'enable', time()+100000000, '/');}

....

//then here is my redirection code
if ('disable' != $_COOKIE['my_Redirect']) {..REDIRECT..}

[westonruter]

There is some support in the Customizer for redirects: https://core.trac.wordpress.org/browser/trunk/src/wp-admin/js/customize-controls.js#L1999

However, perhaps it is not working for initial load.

[selnomeria]

i cant make it work.. i am not proffesional in this case.

[celloexpressions]

I can confirm that the preview fails to load if there is a 301 redirect in place, even if it still points to the same domain, just another page on the site. I'm not sure whether or not this is even something we could fix, though.

[westonruter]

This will probably be resolved with #30028. I suspect the POST data in the Ajax request is getting lost in the redirect, perhaps.

[dlh]

Replying to westonruter:

This will probably be resolved with #30028. I suspect the POST data in the Ajax request is getting lost in the redirect, perhaps.

I couldn't replicate the bug after applying [38810], which suggests this comment was correct.