I have a Windows Vista PC. The latest version of iTunes that can be run on a 32-bit Vista is 12.1.3 (released in mid-September). I upgraded to iTunes 12.1.3 because it can support iOS 9.
Before iOS 9, an iPad Mini home screen "folder" displayed 9 apps per screen in a 3-row by 3-column configuration. With iOS 9, a folder now displays a more generous 16 apps in a 4x4 configuration.
However, iTunes still shows the 3x3 configuration. The actual iPad displays 4x4 apps per folder, but iTunes displays only 3x3. The attached picture shows what I mean.

Favor Request:
If you have:
- A golden oldie Vista 32-bit PC with
iTunes 12.1.3
- An iPad Mini with iOS 9.0 or 9.0.1 or 9.0.2
- A home screen folder you have created
- A sled named "Rosebud" ... this is optional
If you are running iTunes 12.1.3 on a 32-bit PC, please let me know if you also have the 3x3 versus 4x4 display error.
Thanks,
Marty