I think there should be a “no recalc mode” button (next to the native and target modes) so you can color the majority of large challenges very quickly before checking how well they work.
yah on big puzzles and slow workstations it’s a real problem.
or keep it on auto, but only after a couple of seconds of inactivity, maybe light up a green/red pilot light to show if it’s waiting or calculating.
if eterna starts including even larger puzzles, this will become a serious problem. that is, feature!