I checked the emacs tutorial. I don't think we should have a very
special mode in lily4jedit. If we use the lilypond mode, our plugin gets
active. So we can check for a special comment that turns the tutorial
mode on, that - for example - draws some background color for the
indented blocks. The "compile selection" menu function would be quite
easy to do (but not in a context menu, but in the regular LilyTool menu).