Spark roster group properties saving time

When does Spark save groups expand/collapse setting? It seems that it is doing this only when you exit Spark normally. But usually i just shutdown my PC. So in the morning i always had some groups expanded, though i have collapsed them dozen of times every morning and i dont want them to be expanded. Should it save groups state more often?

I would also like to know how Spark remembers which groups were expanded and which groups were collapsed the last time it closed. We would like to have one particular shared group (All Staff) be collapsed by default for our employees.