In GFF you can switch between the display of the Guitar Stave and the Piano Stave. The different views are shown below. A tick mark in the menu reminds you of your choice. If you click on a choice with a tick mark the mark will disappear and the stave will not be shown as well. The staves are adjusted if you change the tuning of your guitar. However, if the full span of the fretboard is used (up to 36 frets) the highest displayed notes will run out of space and into the fretboard.
The middle-C is on the red stave line.
