I have an incremental serial number that I am using to assign part numbers to parts in a specific folder. I had some parts that were copied to this folder from a different folder (that used a different serial number), and when they were copied Regenerate serial number in cards was not checked.

I want to generate a new serial number for these parts, using the serial number from the folder that they are in. I try to do this by right clicking the Part Number box (which is tied to the serial number generator), but the button to Generate next serial number is greyed out.

Any advice on how to enable this button or alternate ways to regenerate the serial number of a part using the serial number generator for the folder that it is in would be appreciated.