After I make some changes the graph changes after a few seconds, what is going on?

Depending on the change you make and how fast you move from screen to screen, there may be a slight delay in order for the many calculations to be completed and the database to be correctly updated. When it does finish it refreshes the graph information. For example, changing a number of settings in Retirement (i.e. change year of retirement and the amount to stream for retirement account income) produces many calculations and updates to the stored data.