A Couple noob questions

[MBCOBRA68]

So does the "s" locker always stay red? I went back to sub school--cruiser was passing right in front of me--had a green triangle-and when I moused over the "s" it still showed poor. I clicked it once and it said good, but still red, and then clicked a second time -said good locked, but still red and definitley not locked onto the ship in the periscope view--thamks again!