_WP_List_Table_Compat::get_column_info()

	protected function get_column_info() {
		$columns = get_column_headers( $this->_screen );
		$hidden = get_hidden_columns( $this->_screen );
		$sortable = array();
		$primary = $this->get_default_primary_column_name();

		return array( $columns, $hidden, $sortable, $primary );
	}