Why is there no syntax-highlighting in KeyNote?
Because an RTF editor is entirely unsuitable for this task. You need a text-only editor to do syntax highlighting. There is a difference in how the coloring is achieved. A text-only editor will color the text on screen, for display only – without affecting the original text file. This way, the program can almost instantaneously change the text coloring, e.g. replace blue color with red, or remove all highlighting altogether. An RTF editor, like KeyNote, cannot do so. The only way to color text in KeyNote is by applying various formatting properties to text. But these changes are permanent: once highlighted, the text would remain this way, and there is no practical way or removing or altering the highlighting. Try highlighting syntax in Word to see what I mean.
