Slider: can you detect a change of activeHandleIdx?

[Walter Lee Davis]

I am building a video editor using Slider to control the position of
the playhead. This Slider has a marker for the start, end, and N
number of captions or inserted still photo overlays. I have a function
which moves the QuickTime movie to a particular frame, and have it
integrated into the onSlide and onChange callbacks. When the sliders
are moved, the movie "scrubs" in real time. But what I lack at this
point is a way to detect if the active handle has changed. I would
like the movie to jump to the frame indicated by the activeHandleIdx
property of the Slider.

Can anyone recommend a way to hook this "focus" event without re-
writing Slider? (I'm trying to maintain a clean script.aculo.us so I
can use Google hosting.)

Thanks in advance,

Walter