While working on my new site I figured I'd try a quick post to it from MarsEdit using Markdown. I've already got the Markdown plugin installed for WordPress and in fact the post looks fine on the blog. The trouble is seeing it in MarsEdit. On the Preview window if I attempt to change the Markdown it snaps back to None or Converting Line Breaks (whichever was previously selected). I see Markdown for a split second. I changed the Defaults for the blog so that the Preview Text Filter is Markdown and this causes it to work, but now if I try to change the Formatting choice in the Preview window it snaps back to Markdown :) Its not really a big deal, but it does seem like an odd UI convention. Why let me interact with the popup if I can't actually change it. The important thing of course is that I could send the post to WordPress and it worked!