I am not sure why editors think a mark up is a good experience. Recently I have seen several editors that have markup on one side, and a formatted/stylized output on the editor. The output only sometimes feeds back to the markup, and usually does not have full functionality. This ends up being slow most of the time, and clicking/dragging/expanding text is not a good experience. They only thing they provide is validation feedback. But you still have worry about closure, indentation, formatting, etc. I usually default to using a light text editor and a shell watching validation.

Is everyone so sick of Windows forms that we can only edit text now? No GUI?