I have used HTML-Kit in the past for my webpages but recently changed my OS to Ubuntu and thought I'd try Screem.   As a test, I copied the content of one of my old pages.   When I went to view it in preview mode, I got the message that it was not an html document.    I suspect that it is because it is technically an XML document (see header below).   Is there a way to identify it in Screem options somewhere so it will be recognized for preview?

Top of file header source:
<?xml version="1.0" encoding="iso-8859-1"?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>The Title</title>
</head>