I've created a new editor settings for a subsite. It displays correctly in the security -> groups -> permissions and I can select it from the HTML Editor Configuration dropdown.

However when I press save, it reverts back to the default, and says successfully saved.

$customEditor = HtmlEditorConfig::get('custom-editor');

$customEditor->setOptions(array(
    'friendly_name' => 'Custom Editor',
    'priority' => '60',
    'mode' => 'none',

    'body_class' => 'typography',
    'document_base_url' => Director::absoluteBaseURL(),

    'cleanup_callback' => "sapphiremce_cleanup",

    'use_native_selects' => false,
    'valid_elements' => "@[id|class|style|title],a[id|rel|rev|dir|tabindex|accesskey|type|name|href|target|title"
        . "|class],-strong/-b[class],-em/-i[class],-strike[class],-u[class],#p[id|dir|class|align|style],-ol[class],"
        . "-ul[class],-li[class],br,img[id|dir|longdesc|usemap|class|src|border|alt=|title|width|height|align|data*],"
        . "-sub[class],-sup[class],-blockquote[dir|class],"
        . "-table[cellspacing|cellpadding|width|height|class|align|dir|id|style],"
        . "-tr[id|dir|class|rowspan|width|height|align|valign|bgcolor|background|bordercolor|style],"
        . "tbody[id|class|style],thead[id|class|style],tfoot[id|class|style],"
        . "#td[id|dir|class|colspan|rowspan|width|height|align|valign|scope|style|headers],"
        . "-th[id|dir|class|colspan|rowspan|width|height|align|valign|scope|style|headers],caption[id|dir|class],"
        . "-div[id|dir|class|align|style],-span[class|align|style],-pre[class|align],address[class|align],"
        . "-h1[id|dir|class|align|style],-h2[id|dir|class|align|style],-h3[id|dir|class|align|style],"
        . "-h4[id|dir|class|align|style],-h5[id|dir|class|align|style],-h6[id|dir|class|align|style],hr[class],"
        . "dd[id|class|title|dir],dl[id|class|title|dir],dt[id|class|title|dir],@[id,style,class]",
    'extended_valid_elements' =>
        'img[class|src|alt|title|hspace|vspace|width|height|align|onmouseover|onmouseout|name|usemap|data*],'
        . 'object[classid|codebase|width|height|data|type],'
        . 'embed[width|height|name|flashvars|src|bgcolor|align|play|loop|quality|allowscriptaccess|type|pluginspage|autoplay],'
        . 'param[name|value],'
        . 'map[class|name|id],'
        . 'area[shape|coords|href|target|alt],'
        . 'ins[cite|datetime],del[cite|datetime],'
        . 'menu[label|type],'
        . 'meter[form|high|low|max|min|optimum|value],'
        . 'cite,abbr,,b,article,aside,code,col,colgroup,details[open],dfn,figure,figcaption,'
        . 'footer,header,kbd,mark,,nav,pre,q[cite],small,summary,time[datetime],var,ol[start|type]',
    'browser_spellcheck' => true,
    'theme_advanced_blockformats' => 'p,pre,address,h2,h3,h4,h5,h6'
));

Is there anything I'm missing here that is stopping it from being correctly enabled?