I am using excel 2007 to look at time series data via pivot tables. I am
importing the base data from a csv flat file into a sheet in excel -- that
all works fine. I have then created a pivot based on the imported data sheet
which has dates as the only enty in the Column Label. When I build the pivot
initially all the dates are in the correct order from the oldest on the left
to the newest on the furthest right. However when I update the underlying
data sheet, by adding another months data and then refresh the pivot; the new
dates are shown in a haphazard order on the pivot. If I rebuild the pivot
from scratch its ok again -- but I want to be able to just refresh the pivot
as I have built other analysis sheets off the back of it. Has anyone else
experienced this or have an idea why it might be happening?

--
Cormac