I've recently had several users ask if the time period selector (Cfilter::addTimeSelector) could be fixed to the top of the screen so that when they scroll on a dashboard with many widgets that the time selector is still visible. I do think this would make dashboards a bit more user-friendly. I think it would be a good change to leave it relative but make it "sticky" as the user scrolls so that they don't have to scroll back to the top of the dashboard to change the time period.