When you click the icon to the right of Air Ticketing Cabin Type Name, the highlighter toggles on or off. The highlighter is a feature that allows you to highlight marks in the view that match a specific value or condition.
You can access the highlighter by clicking the icon next to a dimension or measure in the legend, filter, or parameter. The icon looks like a light bulb with a plus sign. When you click the icon, a highlighter box will appear where you can enter or select a value to highlight. The marks that match the value will be highlighted in the view, while the others will be dimmed. You can also use the highlighter box to search for values, clear the highlighting, or lock the highlighting. To turn off the highlighter, you can click the icon again or close the highlighter box. The other options are not correct descriptions of what occurs when you click the icon to the right of Air Ticketing Cabin Type Name. The filter options do not open, because the icon is not for filtering, but for highlighting. The legend does not toggle on or off, because the icon is not for showing or hiding the legend, but for accessing the highlighter. The Edit Colors dialog box does not open, because the icon is not for changing the colors of marks, but for highlighting them.