TinyMCE 4.x : How to customize toolbar on wp_editor()

Since upgrading to WordPress 3.9 (which includes TinyMCE 4.x), I have problems customizing the editor, displayed via wp_editor()

In the example below, I want to disable the ‘fullscreen’ button, but this doesn’t work.

 $settings = array(  'textarea_name' => 'description',
                 'quicktags' => false,
                 'media_buttons' => false,
                 'teeny' => true,
                 'tinymce'=> array(
                 'theme_advanced_disable' => 'fullscreen'
                       )
);
wp_editor( $content, 'description', $settings );

Unfortunately, the documentation for TinyMCE API 4.x isn’t as helpful to me as the 3.8 one

Try this:

replace

'theme_advanced_disable' => 'fullscreen'

with

'toolbar1'=> 'bold,italic,underline,bullist,numlist,link,unlink,forecolor,undo,redo'

Also, remove 'teeny' => true,