Shiny colours in vertical speed indicator

[lfrivera]

Hello, 

I've been flying the the A350 more than 100 times and today I noticed that my vertical speed indicator in the primary display is showing these shiny colours.

Do you know what it means? How I can activate and reactive? Maybe I press a button without knowing. 

 

Thank you. 
LR

 

 

Edited September 27 by lfrivera

[Stormfish]

It’s TCAS, some aircraft under you and system to avoid collision advise you to maintain positive vertical speed (green zone)

Edited September 27 by Stormfish

[lfrivera]

12 minutes ago, Stormfish said:

It’s TCAS, some aircraft under you and system to avoid collision advise you to maintain positive vertical speed (green zone)

Thanks for your answser. Strange as I was flying alone over the atlantic.