This is quite nice. This is feedback from just using this briefly, but it might be helpful to intercept the tab key and insert spaces when editing, particularly since there's a syntax highlighting section. Maybe also have the preview with iframe option enabled by default as well just to show the fully rendered page.
That aside, I really like how simple and straightforward this is. All of the functionality is clearly labeled and up front. The help documentation is also succinct and immediately useful.
That aside, I really like how simple and straightforward this is. All of the functionality is clearly labeled and up front. The help documentation is also succinct and immediately useful.