Are you referring to two web parts? Or the visibility of the editable text area webpart?

If it is the same webpart, just put all of your formatting into the transformation and use the IfEmpty method to control display.

If you are trying to control one webPart with another, I think you would need to use some scripting to check for the existence of content and show/hide your other content based on that. However, I am no expert, so don't quote me on that ;)

Hello,

The IfEmpty suggestion should work but the PageInfo object has EditableWebParts property which is Hashtable, so you can check the content using PageInfo.EditableWebParts[idofwebpart].

Please let me know if you have any questions.

Best Regards,
Sandro