The actual bug is even dumber than that. I was passing a global 'timestamp' to new_sat, but this is never initialized (it should have been gps->time).

Ofcourse we can look for an empty slot, but that won't do much good as soon as we've seen more than 8 satellites, in which case we would go back to the broken behaviour.

The shade of the bars and the shade of the azm/elv are not the same anymore. The bars are shaded according to whether we received an update from the satellite less than 3 seconds ago. I was afraid it might become visually confusing. Maybe I should stay with using the shade to show if the satellite/measurement is used, and use the 'open bar' to indicate that it is a stale measurement.