1. The colors have changed.
  2. The background-color on the vertical sliders seems to be below the upper slider.
  3. The "handles" gets focus after slide.
JQueryUI 1.7.3
JQueryUI 1.8.6

Screenshots

These screenshots were made from Firefox 3.6.12.

As it can be seen the background does not follow the handles correctly.

1.7.3:

1.8.6: