I'm sure I must be missing something very basic here, but after 2 days of
experimenting and head scratching I would very much appreciate help from one of
you kind people.

I am trying to make a vertical slider bar as an exercise in learning for
myself. (I was successful in making a horizontal slider no problem, so I'm
feeling pretty dumb right now that I can't seem to do the vertical bar too.) I
have a movie clip (VSliderBar_mc) which has 2 movie clips inside - one which is
the track(track_mc) for the slider bar and the second which is a thumb
(thumb_mc) in the shape of a triangle (so that there is a pointer for precisely
where the slider is on the bar). When I am in author mode editing the
VSliderBar_mc I use the align to stage tool palette for the track_mc and align
it to the top. The properties window says the track_mc is at (0,0) with height
of 400 but when I test the slider bar inside a .fla and use trace to see the
track's position, it says the track is at (0,400) and the height is 401. The
thumb (whose point I have at the top of the track_mc's line) in author mode is
at position (0,-8.4) with a height of 16.9 but when I run the .fla in test mode
it shows at position (0,408.5) with a height of 17.9.

What's going on here? I don't get it. Obviously if I am computing where the
thumb is as a percent of the track, being off by 1 pixel on the track length
messes up any precision and I never get a 0 value at the start of the track.
Plus I want to use the draw API to fill in the track up to where the thumb is
and I need to know the correct position to start drawing (0,0) or (0,400)

I must be doing something really dumb. Thanks in advance for anyone who can
help me.:confused;