WYSIWYG mode pretty much destroys all HTML tags, except for a very small subset that it could have generated itself through the editor buttons. And even then it will destroy almost any property of such tags (such as id, style or class).
I have removed the Source button from CkEditor, which makes the Format button the only way to switch it between HTML and WYSIWYG mode, and I have put a confirm box on the Format button to warn anyone who uses it to select WYSIWYG mode. Besides that, I have edited the text about each format to make it clear that WYSIWYG is not recommended, as it can alter your HTML.
I have removed the Source button from CkEditor, which makes the Format button the only way to switch it between HTML and WYSIWYG mode, and I have put a confirm box on the Format button to warn anyone who uses it to select WYSIWYG mode. Besides that, I have edited the text about each format to make it clear that WYSIWYG is not recommended, as it can alter your HTML.