Update 1:
Seems theres a bit more stuff that may mess up templates dropdown in pages. When you define your child-theme in it’s gloriously new style.css it seems it can NOT contain any kind of special characters. Since i live in Sweden and time to time i need to use åäö and ÅÄÖ i just added these in my child-wp-template style.css file and there you go, template dropdown is not showing up.

Not ok to use:

/*
Theme Name: WpTheme using Å in its name
Theme URI: http://as3breeze.com
Description: Template with Å
Author: Danel
Author URI: http://as3breeze.com
Template: åtemplate
Version: 1.0
*/

This is ok to use:

/*
Theme Name: WpTheme using Å in its name
Theme URI: http://as3breeze.com
Description: Template with Å
Author: Danel
Author URI: http://as3breeze.com
Template: åtemplate
Version: 1.0
*/

 

Problem:
A while ago i encountered a problem with my custom page templates. In page attributes i could not see my page-templates inside the dropdown menu still i had declared template names in each page-temple php file and even if i had lots of custom templates… still nothing in dropdown-menu.

Cause:
I had few hour earlier made a duplicate of my wordpress-theme folder, inside theme folder, as a backup.

Solution:
Activate another wordpress theme under Theme-handler and there after re-activate your own theme. After i re-activated, i then could select my custom page template in Page attributes dropdown.