Form field calculation tab is grayed out

[Carol24105057x4h4]

I'm using Acrobat Pro.

I have 13 number fields and I want to calculate the sum in the 14th field. 

I went to the Calculation tab and selected "Value is the [sum] of the following fields". I selected the 13 fields but they don't appear in the Pick box. 

What am I doing wrong?

thanks for your help!

[try67]

Which fields did you select?

[PDF Automation Station]

Where did you select them?  Can you screenshot the window after you click the Pick button please?

[JR Boulay]

This is an old bug in Acrobat for Macintosh.
What is your version of Acrobat?

[Carol24105057x4h4]

I'm on a PC with the latest version just downloaded a few weeks ago.

I don't know if this is a new bug but I did get it to work by changing the alignment of the number fields to "right". It worked immediately. 

[PDF Automation Station · Accepted solution]

Strange.  Just a tip:  If you use Right-click > Create muliple fields to create your fields in a column with numbered suffixes (Example:  Create 13 fields from field A to get A.0, A.1, A.2....A.12) you only have to select one field ("A") in the picker to sum them.

[JR Boulay]

You can use the Simplified field notation:

A1 + A2 + A3 + ... + A13