Focus Mode allows you to focus on the currently selected line of a song. When enabled all chord symbols in the lines above and below the selected line are replaced with position markers.
Focus Mode allows you to select a specific position within a word more easily. When Focus Mode is disabled there is a slight delay when selecting a new position: Song One has to interpret whether a word is selected or a chord is to be played.
To enable (or disable) Focus Mode tap/click on the four lines of the docked toolbar. (If the docked toolbar is not visible tap/click on the three dots in the right corner of the main toolbar.)
A position marker represents an actual chord. It can be repositioned or swiped to copy the chord located at the marker position to a new location.