I currently have version 1.9.6 and will probably upgrade this next summer but anyway I made a weird discovery today. If I type the word UNDEFINED into any HTML Editor I can't save it or toggle to the HTML. I discovered it by asking a math question where I was talking about an undefined slope. As long as I had the word undefined anywhere in the box I can't save it. Any ideas?
you could try to cast the variable to a string? (string)$data
Sounds like it's taking UNDEfINED literally.