CX-Programmer Reusable File Greyed Out

I am trying to use Reusable files, but it is greyed out. Is there a setting that needs to be enabled to activate it?

I am using CX-Programmer v 9.74

Welcome to the forum,
When CX-One installed, there are online manuals that also install.
There are some restrictions on Reusable Files.
Check the CX-Programmer Operation Manual, pdf pages 114, 135 and 211 for more information.
gtsuport

As per cx-programmer manual:

When any structure definitions exist on the data type view, you cannot select the Function Block (Ladder) Generation menu item or the Reusable File | Save as... menu item in all sections.

@gtsuport and @Manthan thanks for your quick feedback, I managed to determine this experimentally this morning.

I have attached the link of the manual that i was looking at but this one only tells you how to use it not why it won't work.

https://assets.omron.eu/downloads/manual/en/v6/w446_cx-programmer_operation_manual_en.pdf

Is there a different manual that I should be looking at, or am I just being blind.