Hey Rob, try the following:
Double-click on the field which has the drop-down, and then click on the button labelled "Advanced..."
Then in the "Autosort options" section on the left of the dialog that appears, select "Ascending". Also ensure that the "Using field" drop-down contains the name of the field whose contents you want sorting alphabetically.
Click OK to both dialogs and check the result.
I have an excel workbook that contains 2 worksheets - a raw data worksheet and a pivot table worksheet. I have added some rows to my raw data worksheet and when I refresh my pivot table, those new items are placed at the bottom of the drop down, rather than in alphabetical order. is there a way to fix this so that they are in alphabetical order ?