Last modified: 2010-05-15 15:50:57 UTC
In case these matter:
* PHP: 5.2.1 (apache2handler)
* MySQL: 5.0.38-Ubuntu_0ubuntu1-log
Create a page with this content:
Now click the  for Header 2. Change the "X" to "Y". Click "Save page".
As you can see, all sorts of interesting and unexpected things happened. Header 2 got slurped inside Header 1 and there's a new Header tag: X with contents "</pre>"...
Kooky, eh? I'm having to [undo] many errant "Save page" operations daily. Large pages with lots of <pre> headers get contorted in all sorts of bizarre ways.
Thanks for your help,
This was fixed for 1.11 some time ago.
*** This bug has been marked as a duplicate of bug 10309 ***