In the .htm for the slider, I failed to include the line:

onmousemovevaluechange="moi.ui.fireUIEvent(id);"

Including this code results in the "bulge" of the curve trying to respond to the mouse movement in a continuous way,
but apparently each (pixel change?) causes recalculation, so the curve flickers for dozens of times, due to relatively slow (?) javascript.

I'll try putting some of the calculations in the .htm file.

- Brian