With OS X Lion Apple introduced new scroll bars on Mac OS X. The scroll bars are very different from Windows scroll bars:

1. They are much smaller,
2. they have no arrow buttons,
3. they are monochrome,
4. they take up no space but rather overlay on the contents in the window,
5. they are semitransparent,
6. they are invisible until you start scrolling using your mouse wheel or pad guesture.

With JavaFX 2.1.0-beta-b19 the scroll bars I get out of the box look like traditional Windows scroll bars (none of the points 1. - 6. above are adhered to).