I just Add content region in essential theme, i do use my-moodle and in Appearance>Default My Home Page i could not add a block to the content region

I just add the region to mydashboard and mypublic arrays in the theme/essential/config.php:

// My dashboard page.
'mydashboard' => array(
'file' => 'columns3.php',
'regions' => array('side-pre', 'side-post', 'footer-left', 'footer-middle', 'footer-right', 'content'),
'defaultregion' => 'side-post',
'options' => array('langmenu'=>true),