title: Error with output buffering and FirePHP
body: <p>I get unexplained "Headers already sent on line #..." error on those 2 lines that execute "echo ..." in the code below.</p>
  
  <p>Simplified version of the case:</p>
  
  <pre><code>&lt;?php
  ob_start();
  
  //Initializing FirePHP...
  include_once(F_FS_PATH."lib/FirePHPCore/fb.php");
  // &lt;--- I've also tried to move the ob_start(), after the FirePHP init,
  // &lt;--- instead before it. But it made no difference.
  ?&gt;
  &lt;html&gt;
  &lt;div&gt;A lots of HTML (and php) code goes here... Actually my entire page.
  FirePHP is also used here many times by multiple invocations
  of the function fb('debug text');&lt;/div&gt;
  &lt;/html&gt;
  
  &lt;?php
  $all_page_content=ob_get_clean();
  
  if ($GLOBALS["marketing_enabled"])
      echo marketingReplaceContent($all_page_content);
  else
      echo $all_page_content;
  
  ob_flush(); flush();
  
  //Do some other non-printing - but slow stuff.
  do_the_silent_slow_stuff_Now();
  
  // &lt;--- presumably the php execution ends here.
  ?&gt;
  </code></pre>
  
  <p>I cannot understand why FirePHP is trying to do something upon page completion after I print the buffer and flushed it? Or what is it trying? How can I cope with this problem? :(</p>