I've created a Wordpress theme that uses several custom page templates. As per the documentation http://codex.wordpress.org/Pages#Creating_Your_Own_Page_Templates I've accomplished this simply by setting a comment at the top of my template-files:
/* Template Name: MyCustomTemplate */
And it's worked fine for as long as I can remember (it's not the first time I use custom page templates). Today we updated to Wodrpress 3.4 and suddenly the option to select a custom template has disappeared from the admin (it used to be a drop-down in the "Page Attributes" box to the right). However, if you use the "Quick Edit" in the list of pages the "Template" drop-down is still visible, but you can only select "Default template" - none of the custom templates that I've set up.
According to this blog post: http://nacin.com/2012/03/29/page-templates-in-subdirectories-new-in-wordpress-3-4/ WP 3.4 has added support for custom page templates inside a sub-directory, but it's unclear whether this directory needs to be named something special or if you still need the "Template Name"-comment at the top of the files. I've tried creating a "pages"-directory and first put an empty .php-file in it but that did nothing. I then tried putting one of my custom page templates (complete with the "Template Name"-comment) in there but that didn't help either.
It's worth noting that the pages that were already assigned to use a custom page template still render with that template - even though it says "Default template" in "Quick Edit" and there are no other templates available in the drop-down.
There's almost nothing to be found on the interwebs yet but I'm hoping one of you will know what's going on.