Sliders snap to increments of 2

1. Add the SCurveTonemap effect to a presentation.
2. Select the effect in the Timeline.
   Properties for the effect appear in the Inspector Control (correct)
3. Drag the slider for Saturation Level property

EXPECTED: Slider moves continuously and adjusts value with floating point granularity.
ACTUAL: Slider pops between 0 and 2, the min and max values, with no chance to select any value in-between.

Similar problems with other sliders lead me to believe that the sliders are locked to values of "minValue + 2n" for non-negative integer values of n.