As you know, Creative Flash Scroller acts like a mask to the targeted movie clip. We can adjust the masking behavior from the Mask tab of the Component Inspector.
Adjust the mask options
The first option allows us to decide wether we will use a personalised mask or not. For Classic Scroller, the None position at "Transparent mask" means that the scroller will appear as default, without any changes. The other two options are "Horizontal" and "Vertical" (masks); this means that the scrolling area will have an alpha gradient aspect, with transparent character in the middle and opaque (white) character on the sides (top and bottom for horizontal, left and right for vertical).
The next parameter, "Transparent zone size", configures the "Vertical" and the "Horizontal" masks; the lowest value (0) means that the visible (transparent) area will be minimum, while the highest value (100) enlarges the visible area to maximum. Nevertheless, the horizontal/vertical mask is kept even for the extreme values (0/100). This parameter represents a percentage (of the scrolling area).