What is the meaning of the lights

[nemo69]

  dens.jpg (Size: 2.8 KB / Downloads: 6)

I suppose you're speaking of something like the illustrated example above. The light can go from green to red through yellow and orange. It's the target density indicator. The higher it gets, the more penalties and casualties you'll suffer if attacked. See the manual, section 13.7 Target density for more detailed explanations.

Hope it helps.