Pivot tables lose of data fields when selecting
 

Having an issue with setting up pivot tables not to lose certain
fields if users de-selects some. For example I have muliple column of
data.

a, b, c, d, e, f

The user de-selects d, e, f; The next time they want to see D, E, F.
The go back to the drop down menu and only see Show all, a, b, c. Is
there anyway I can always keep them so they can reslect the data? I
can go back into the wizard and add them back but that is time
consuming and tring to teach that to 30 users is a bit tricky.