CKEditor from CDN does not load in Panels IPE when a form is loaded in a popup for the first time.

Reported in #1936570-9: CKEditor doesn't attach on first ajax loaded form and on multiple ajax loaded forms the text-filter switch doesn't work by loopduplicate.

After some investigation it turned out, that the problem is in different domain from which ckeditor.js is loaded.

I narrowed down the issue to a single line in ckeditor_load_by_field(), if the following line is used (ckeditor.js loaded from the same domain):

drupal_add_js( 'sites/all/libraries/ckeditor/ckeditor.js', array('type' => 'file', 'scope' => 'footer', 'preprocess' => $preprocess));

then CKEditor loads.

However, when ckeditor.js is loaded from a remote (external) URL:

drupal_add_js($editor_url_path . '/ckeditor.js', array('type' => 'external', 'scope' => 'footer'));

then somehow, when the panels popup is loaded for the first time, ckeditor.js is not yet loaded and parsed, and CKEDITOR object is still undefined.