slider orientation default seems incorrect more often than not...

slider orientation default seems incorrect more often than not...


When someone has time, could you explain the logic behind how the
slider decides which orientation to use?
I've had to fix our select-to-slider wrapper plugin to always set
'horizontal' as a default because it would flip to vertical even when
there was plenty of room for a horizontal slider (~400px width).
At a glance, it seems maybe the logic should be...
if the number of slider values on the scale is greater than the pixel
width, set to vertical.
otherwise, set to horizontal.
Otherwise, it seems vertical sliders will be occurring in many
situations where horizontal is expected, since horizontal seems to me
to be the primary case in most interfaces.
Thoughts?