I just checked the website for FCKEditor. It looks like the Safara/Opera issue has been addressed. As this is the default editor for DotNetNuke, I would expect to see this show up later. I
From fckeditor.net:
October 10, 2007 - FCKeditor 2.5 Beta released (What's New?)
After an incredible development period, full of challenges and enriched by brilliant ideas, here we are with the Beta for the most important release of FCKeditor since version 2.0. It brings not only Safari and Opera support, but also introduces incredibly powerful features.
The new Style System gives full control of the generated markup to developers' hands. Why having a limited interface to achieve a XHTML 1.1 experience? Enjoy a full featured editor, while well controlling how things work on it. No more
tags? Well, the system is so flexible that it is up to you to decide (but don't worry... no tags by default 
).
Do you want more? What about blockquote support, the revamped Undo System, the Data Processor which makes it possible to handle non HTML data, and much more. And of course, lots of bug fixes.
It's too much to describe in these few lines. So, go ahead with FCKeditor 2.5 Beta, and enjoy a new editing experience!