I'm extending LeftAndMain to create a custom CMS area. This is loosely based on the Settings area of the CMS.

After looking into how the Settings area is put together in code, I noticed this function that sets the theme to display tabs correctly:

     public function getResponseNegotiator() {
		$neg = parent::getResponseNegotiator();
		$controller = $this;
		$neg->setCallback('CurrentForm', function() use(&$controller) {
			return $controller->renderWith($controller->getTemplatesWithSuffix('_Content'));
		});
		return $neg;
	}

This gets a template located in /cms/templates/Includes/CMSSettingsController_Content.ss

So I duplicated this in my custom LeftAndMain child and created a duplicate template. This is not a module as it is very specific to the application and we want to keep code/templates in one area of the file system.

When I do the same as above, getTemplatesWithSuffix only returns LeftAndMain.ss.

I have stepped through the code and found that even though my custom template is found, it is ignored because $theme is null in this subsequent function:
SSViewer.php

public static function hasTemplate($templates) {
		$manifest = SS_TemplateLoader::instance()->getManifest();

		if(Config::inst()->get('SSViewer', 'theme_enabled')) {
			$theme = Config::inst()->get('SSViewer', 'theme');
		} else {
			$theme = null;
		}

		foreach ((array) $templates as $template) {
			if ($manifest->getCandidateTemplate($template, $theme)) return true;
		}

		return false;
	}

So how do I make the CMS aware of the theme? Or is a way of doing this?

Worth adding: Theme is set in config.yml like so:

---
Name: mysite
After: 'framework/*','cms/*'
---
# YAML configuration for SilverStripe
# See http://doc.silverstripe.org/framework/en/topics/configuration
# Caution: Indentation through two spaces, not tabs
SSViewer:
  theme: 'mytheme'

I thought the After: might have been the culprit, but even if I remove it entirely and do a dev/build, the CMS still can't get hold of it.

The CMS deliberately unsets the theme, so it won't load templates from there. Put the templates in mysite/templates/ instead.

Thanks Simon,

I wasn't really interested in separating this one template from the rest of the codebase (for future maintenance reasons). But your suggestion did work.

In then end I was able to get the template to load from the theme directory by adding this to my LeftAndMain extended class:

public function init() {
	parent::init();
	
	Config::inst()->update('SSViewer', 'theme_enabled', true);
		
	...
}