Excel 2010 Pivot Table Field List will not display

On one user's PC, Excel 2010 on Windows 7

Any new or existing pivot table will not display a Field List. the ribbon button when clicked does not show colour, right click on the pivot table to select Show Field List does not work either.

I have also tried using the Immediate window in VBA. Typed 

ActiveWorkbook.ShowPivotTableFieldList =True

and then pressed Enter

Still not displaying Field List.

I have also tried minimising, maximising and moving the worksheet around - no luck.

In Safe Mode the field list will show.

I have tried re-installing and repairing the installation. No luck.

Any suggestions?