Created a custom screen.
Set my refresh time to 30/60/whatever seconds.
Set period to 1 day.

What happens is that the page does 'reload' at the interval specified by my refresh time,
but the graphs do not change. They continue to show only up until the time I first loaded
them.

The problem appears be be because of the "stime" parameter appended to the URL.
I assume it means "start time" and refers to the latest time up to which
the graph should show data. Since "stime" never changes from the time I first start
viewing the screen, the latest data does not get shown on the graph.

I've found if I just remove the "stime=" parameter from the URL, it does behave how I
would expect. That is, the graph gets updated to the current time on each refresh.