Right now It is possible to select 'this month' and 'last month'.
Dashboards reporting about 'last month' often include reportlets about
'the month before last month'. As this is not a preset date range, the
month is selected manually. When this date range is rolling, the viewers
almost never see data about the intended date range.Still, 'rolling' is
definitely the option to use, as 'fixed' will force you to update the
dashboard each month. Therefore I suggest a preset date range for 'month