Am I missing something - editing HTML in Irida

Whenever I edit my HTML files in IDEA, the entire window is covered with red underlines. Every single character on the screen is underlined, the error is "Top level element is not completed."

If I remove the declaration, then a bunch of tag names are highlighted in red, like and and <img>]]>.

If I remove the DOCTYPE declaration, it works okay, but publishing HTML without a doctype sucks (and it also affects how browsers render the page), so I can't just remove all my doctype declarations. I want to use XHTML.

Anyway, is there something I'm missing? Does Irida not support XHTML yet? Or should I be editing in some other way or with some other configuration?

I've attached an example of one of my HTML files, in case that helps figure out the problem.