When i open a gpx file and it shows me a track, the line is thin and ranges from green to blue. In a separate pane below the map is the name of the track, its length,etc. If i double click on the name, the track then becomes highlighted in yellow and the words "track display on" flash on the map. If i tick/untick the box next to the track name, the track appears/disappears as it should--but it is always highlighted in yellow? What is the significance of the yellow highlight and how do i get rid of it?