I am using GnuCash 1.8.1 as installed with RedHat 9.

I have an account, say, Expenses:taxes:Sales Tax with no subaccounts.
It has many debits - when I buy something, and some credits - when I
return a purchase.  (All of these are splits because the tax is just a
portion of the total bill on each purchase but I don't think that is
related to the problem.)

I double click on the account to open the Register.  (I select a date
range to reduce the size of the report - again, I don't think this is
related to the problem.)

I click the Report button on the toolbar (or in the menu, Reports >
Account Report) and the report shows up as another tab back in the main
GnuCash window.  The report is titled "Expenses:taxes:Sales Tax - Register
Report".  So far so good.

The problem is I need the report to show a debit total at the bottom of
the debit column and a credit total at the bottom of the credit column.
 All it shows is the net total of debits minus credits.  (Which, if
Running Balance option is selected, and if the date range starts at "show
earliest", is the same as the Running Balance on the last line.)

I figured the Totals checkbox in the Report options would do this, but
as far as I can see, it causes no change to this report whatsoever,
whether selected or deselected.  This is the bug, the Totals checkbox does
not add totals to the report.

The help describes this checkbox as "Totals: Charts display totals in
the chart legend if this option is selected."  which it seems only
applies to the more graphical reports like pie and bar charts that
actually have a Legend.  But if so, it should be removed from the
Register report (I would vote against this "solution" because there are
many cases where the total debits and total credits are needed - like on my
tax forms for instance).  The better solution would be to correct the
Register report so the Totals option behaves as expected.