Pivot Table Sorting Problem

My Pivot Table won't sort manually!

My Pivot Table has TWO sets of values shown in TWO columns (Units & Dollars).
[ Each row of my Pivot Table has TWO "fields" i.e. PRODUCT & PRODUCT-ID ]

The underlying data table has rows for each DAY. I then GROUP these days in the Pivot Table into MONTHS (in the columns area).

I select inside the PT in EITHER one of the (monthly) UNITS or DOLLARS columns -----OR----- I select in one of the Grand Totals COLUMNS for either UNITS or DOLLARS.

I click on DATA (in the ribbon) and SORT (Ascending e.g.). NOTHING HAPPENS!

Why?

I am using Excel 2011 for Mac.

Do you have a sort on the product or the product ID that is taking priority?

I don't think so but I find it very hard to tell. There seem to be so many locations for Sorting. How do I tell definitively?

remove the fields that could be at issue, then put them back in again.

I just removed the PRODUCT-ID field and I see some changes:

I can now sort on the MONTH cols (both the UNITS and the DOLLARS cols).
I still cannot sort on the GRAND TOTAL cols though (both the UNITS and the DOLLARS cols).

Any ideas?

Also --

I've just removed the UNITS cols and I see further changes:

I can now sort correctly on all cols (DOLLARS) -- both the individual MONTHS and the GRAND TOTAL col.

When I put the UNITS col back I see the behaviour mentioned in the message directly above:
I can now sort on the MONTH cols (both the UNITS and the DOLLARS cols).
I still cannot sort on the GRAND TOTAL cols though (both the UNITS and the DOLLARS cols).
-- Does having the TWO values cols affect sorting on the GRAND TOTALS cols? I don't see why it should.

FYI -- When I select in 1 of the 2 GRAND TOTALS cols and SORT the entire cols swap places ??? (and nothing sorts).

Can anyone comment?

e.g. When I select in 1 of the 2 GRAND TOTALS cols and SORT the entire cols swap places ??? (and nothing sorts).
I've seen this strange behaviour in multiple PT's.