User-selected application icons can be added into a control center interface. The corresponding applications may be accessed either from the springboard or from the control center interface. Operation of slider controls in the control center interface can temporarily fade out all aspects of the control center interface except for the slider control being operated during that control's operation. The temporary fading out of most of the other aspect of the control center interface causes the content that had been at least partially obscured and overlaid by the previously opaque control center interface to become visible during the slider control's operation. While the slider control is being actively operated, the control center interface becomes transparent except for the control itself. Consequently, the effects of the slider control's operation relative to the value of the parameter to which it pertains are immediately apparent during that operation.