Revisiting the post to try to get an editable sidebar working in SS3...
Discovered that "Root.Content.Sidebar" is deprecated in Version 3. PHP code needs to change to the following...
<?php
class Page extends SiteTree {
static $db = array(
'SidebarHTML' => 'HTMLText'
);
static $has_one = array(
);
function getCMSFields() {
$fields = parent::getCMSFields();
$fields->addFieldToTab("Root.Sidebar", new HtmlEditorField( "SidebarHTML"));
return $fields;
}
}
class Page_Controller extends ContentController {
}
?>
Hopefully this will help others in a similar predicament!