Slider Doesn't Always Move

The sliders don’t always move when the sliders are at the minimum position. For example, when the sliders are setup as outlets with r, g, and b values set to 0, none of the sliders will move by dragging the little ball. The only way I can get them off the min position is to click on the slider bar. Then I can drag the slider ball.

Why is this happening? Did I program something wrong or is this a bug in the slider or a feature of the sliders?

Additionally, when I changed the alpha value to a fraction like 0.5, I get a division of the ColorWell running from the bottom L/H corner to the top R/H corner. What is that for?

Thank you…
Earl Staley