Alpha blending

Avoid using the alpha property, when possible.

Avoid using effects that require alpha blending when using the alpha property, such as fading effects. When a display object uses alpha blending, the runtime must combine the color values of every stacked display object and the background color to determine the final color. Thus, alpha blending can be more processor-intensive than drawing an opaque color. This extra computation can hurt performance on slow devices. Avoid using the alpha property, when possible.