On line 4046 of coursepress.php in the CoursePress Plugin (v 18.104.22.168), there is the following line:
wp_enqueue_script( 'jquery-ui', 'http://code.jquery.com/ui/1.10.3/jquery-ui.js', array( 'jquery' ), '1.10.3' ); //need to change this to built-in
wp_enqueue_script( 'jquery-ui', '//code.jquery.com/ui/1.10.3/jquery-ui.js', array( 'jquery' ), '1.10.3' ); //need to change this to built-in
This mixed content is causing jQuery to not be recognized and therefore causes the pages selector in the Unit to not show.
I'm also recently having some troubles where none of my Pages, Units, or Elements will save. When I attempt to save, they are cleared out and I'm left back at the default empty view. I can see they are indeed being written to the database, but are not being loaded into the Unit creation view. Any ideas on what would be causing this extremely odd behavior? Note* I do not get any errors or warnings, the content just disappears.