1) open the editor at page http://cutesoft.net/example/Edithtml.aspx
2) switch to HMTL mode
3) add a reference to a CSS file in the <head> section
4) switch to Normal mode
5) switch to HTML mode and recheck the HTML
6) u will get an extra "</li>" in the <head> section:
<html>
<head>
<title>test</title>
<meta content="gf gfd td " name="description" /></li>
<link href="style.css" type="text/css" rel="stylesheet" />
</head>
<body>
<img alt="" src="http://cutesoft.net/uploads/cindy_crawford.jpg" border="0" />
</body>
</html>
Also I wonder since u can edit the "Page Properties" like DOCType, Title, Keywords etc., wouldn't it easier for the users if they can add stylesheets reference with that same screen instead to do that in the HTML mode?