".make_form(make_link("source_history/revert"))."
					
					".html_escape($name)." $h_ip";
            $history_list .= '
				
					'.$image_id.' :
					'.$current_source.' (Set by '.$setter.')
				 
			';
        }
        $history_html = $start_string . $history_list . $end_string;
        $page->set_title("Global Source History");
        $page->set_heading("Global Source History");
        $page->add_block(new Block("Source History", $history_html, "main", 10));
        $h_prev = ($page_number <= 1) ? "Prev" :
            'Prev ';
        $h_index = "Index ";
        $h_next = 'Next ';
        $nav = $h_prev.' | '.$h_index.' | '.$h_next;
        $page->add_block(new Block("Navigation", $nav, "left"));
    }
    /**
     * Add a section to the admin page.
     */
    public function display_admin_block(string $validation_msg='')
    {
        global $page;
        
        if (!empty($validation_msg)) {
            $validation_msg = ''. $validation_msg .' ';
        }
        
        $html = '
			Revert source changes by a specific IP address or username, optionally limited to recent changes.
			'.$validation_msg.'
			'. $title .' 
';
    }
}