What is this icon for?

[Palliz]

Been researching for ages - went through user manual - can't find what this particular icon is for - anyone?

 

[Kilrah]

Erases your current track on the map.

 

[Palliz]

Erases your current track on the map.

Thanks - been looking everywhere for this.....lol
would press it & not notice any difference at all - now got something to look for next time
Cheers