The wysiwyg javascript tool for editing html components is currently broken.
This appears to be because the code for doing listing the IDs of each HTML textarea doesn't work, this is the code that is used to generated a list of the HTML components:
<?for name="element self/components --html"?>${element/block_name}<?end?>
If this code is added to templates/admin/content/en.html, for example in a <h2> tag then a few html components are added to the page and moved up and down it becomes clear that it doesn't generated a usable listing of the HTML components in the page — it is not updated as elements are moved up and down the page but if you view source the items IDs are updated.
TinyMCE
Since there is no longer a need to use a BSD textarea editor it probably makes sense to switch to TinyMCE http://tinymce.moxiecode.com/