In terms of cross-platform development I understand wanting to use browser technologies, but these off-line web-applications always feel so flaky and unintegrated. The Atom editor for example still can't switch languages for the spell-checker at runtime, even though browsers themselves can.

> I don't have any recommendations for Linux, unfortunately.

Vim works just fine for MarkDown, Gedit is not too bad either. The whole point of MarkDown is being readable both as text in an editor and formatted by a renderer.