Zoom profile help
Type: "[startDistanceInKM] [endDistanceInKM]".
An empty startDistanceInKM means start (km 0);
an empty endDistanceInKM means track length
Clear textbox in order to restore full profile range
Examples:
- "10 20" zoom profile from km 10 to km 20
- " 20" zoom profile from km 0 to km 20
- "20 " zoom profile from km 20 to the track length
- "" restore full profile range