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// Remove All Dashboard Widgets
function remove_dashboard_widgets() {
    global $wp_meta_boxes;
    unset( $wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press'] );
    unset( $wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links'] );
    unset( $wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now'] );
    unset( $wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins'] );
    unset( $wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_drafts'] );
    unset( $wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_comments'] );
    unset( $wp_meta_boxes['dashboard']['side']['core']['dashboard_primary'] );
    unset( $wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary'] );
  remove_meta_box( 'dashboard_activity', 'dashboard', 'normal' );
}
add_action( 'wp_dashboard_setup', 'remove_dashboard_widgets' );