Well, MagicTree is written in Java, so in theory we shouldn't need to port anywhere. But, as they say, "In theory, theory and practice are the same. In practice, they are not." Actually most things worked without any porting, which is a good thing. Still, a few things had to be done.
To get more Mac OS-like look and feel we had to make MagicTree show the menu bar on top of the screen, rather than in the main frame, respond to application menu items, such as "About" and "Quit" (and remove those menu items from File and Help respectively) and to get the application icon look pretty.