Issue: text area goes blank upon toggle of editor switch

This is due to vBulletin 4 not being compatible with PHP 5.4. The only way to avoid it is to turn error reporting off, but we need that on the development site. I'm marking this as vBulletin Bug as the errors thrown are from vBulletin code, not VaultWiki code. I would advise against using the editor switch on the dev site.

I have already opened a report about this when ckEditor was implemented during summer 2011: if an error occurs during editor switch, the switch should fail elegantly, rather than eradicating the editor content. But it doesn't look like they heeded my advice.

Ah yeah. Nothing to do about that. Problem is that vb4 might never be compatible with PHP5.4 and 5.5 is already around the corner.
IB is pushing for vb5 sales. If it gets fixed then it will take a lot of time. Meanwhile hosts are moving their servers to PHP5.4

As a side note: the new CKE version is out.