Hello everyone,
As you may well know, SMF 2.0 is still in its pre-release stage, as the current version installed on Ichiraku is Release Candidate 1.1. As it’s not the final release yet, we are expecting some bugs to crop up once in a while, so we are very, very critical of the system’s performance and are always on the lookout for issues that may manifest as users utilize it for their purposes.
A somewhat frustrating bug has appeared for users of Firefox, Safari, and Google Chrome (we have tested it on Internet Explorer 8 and Opera 9.6 without any error, so if you are users of these browsers, this issue does not concern you). This is a rather annoying problem to users of the SMF Rich Editor, commonly called WYSIWYG (what you see is what you get). This is a new feature of SMF 2 that enables users not familiar with BBCode like [img] or [b] to format their posts and see in real-time, within the posting window, what their posts would look like when submitted. However, a problem with the coding, as described in this article, there is an acknowledged bug in SMF 2.0 that will be addressed in the second Release Candidate of SMF 2. To quote:
The new lines thing is a bug in Webkit.
Webkit wraps lines in iframes in <divs>
To see the entire article, click THIS.
Basically, what happens is that when you try to format an entire post with several line breaks, SMF’s WYSIWYG editor automatically cuts the line breaks from them and jams them all together in one big paragraph.
We have already submitted a report to the developers regarding this issue.
A few images of the problem using Firefox:

Test message using single line of text.
As you can see here, you can format your text with as many combinations of style as you can think of, and it would appear as nice as it appears in the window AS LONG AS THERE IS NO LINE BREAK. However, when line breaks are involved, this:

Test message, with several line breaks
You will see that all line breaks were removed, and that there was an additional [/] after your text.
We have found however that you can actually work around this issue by inputting one whole block of text, formatting them, and then dividing them into paragraphs. The problem seems to be triggered by typing several paragraphs then formatting them afterward.
Again we are working with the SMF developers to fix this issue, so until the issue is fixed, bear with us. Otherwise, use Opera or Internet Explorer for the meantime if you want to use the WYSIWYG editor without complications, or manually format your posts using BBCode or using WYSIWYG one line at a time.
Cheers,
Ichiraku DEV