Template page--node--.tpl.php not working I've created a page node for an about page. I've checked the node id of the node which is 11.
I've created a file named page--node--11.tpl.php in my theme directory containing some test html but it's not overriding the standard page.tpl.php file.
I've also tried using the following file names:
page-node-11.tpl.php
page-node--11.tpl.php

I've cleared the cache but still no luck.

What am I missing?
According to Drupal 7 Template (Theme Hook) Suggestions it should be page--node--11.tpl.php (note the double dashes):


  page--[front|internal/path].tpl.php
      base template: page.tpl.php
  The suggestions are numerous. The one that takes precedence is for the front page. The rest are based on the internal path of the current page. Do not confuse the internal path to path aliases which are not accounted for. Keep in mind that the commonly-used Pathauto module uses path aliases.
  
  The front page can be set at "Administration > Configuration > System > Site information." In Drupal 6, at "Administrator > Site configuration > Site information." Anything set there will trigger the suggestion of "page--front.tpl.php" for it.
  
  The list of suggested template files is in order of specificity based on internal paths. One suggestion is made for every element of the current path, though numeric elements are not carried to subsequent suggestions. For example, "http://www.example.com/node/1/edit" would result in the following suggestions:
  
  
  page--node--edit.tpl.php
  page--node--1.tpl.php
  page--node.tpl.php
  page.tpl.php
  
  
  Also see page.tpl.php in the Drupal API documentation for more information.