A while ago I read John Novaks great rant on how hard and annoying it can be to do something as simple as extending a cross-platform application with the simplest of GUIs. Or as he puts it:
You must not under any circumstance try to open a window (on the computer, I mean), attempt to change the colour of a single pixel in it, or—god forbid!—fantasise about using native (or any kind of, for the matter)…