Button next to the envelope symbol...what does it do?

[fxe1200peter]

Hi and I am currently doing the Vendee Globe and can someone please tell me what the button at the bottom of the screen next to the envelope/message symbol does on the dashboard of offshore regatta? It lights blue when I press it but I don't see anything happening. Thx in advance Pete UK

[JinSooKi Sidels Family]

Hi good morning. 

Previously it was the radar to detect nearby boats. I actually have the same result as you = NOTHING 🤪