An application for a slider bar on a display has a series of ticks, each indicating one or more gradations of a parameter ranging between a minimum value and a maximum value. Two marker icons are on the display screen in relation to the ticks. A user control moves a first marker icon within a predetermined range of ticks. Once the first marker icon reaches an end of travel, if the end of travel is next the second marker icon, the first marker becomes inactive (remaining at its current location) and the second marker icon becomes the active marker icon, moving within a predetermined range for the second marker icon.