Hidden columns Northwind db

[Gavx]

Trying to learn more about Split Forms.
Looking at the Northwind DB, Customer List form I notice that not all of the columns are displayed. Can someone explain how this was achieved.

Thanks

 

[June7]

Right click on column header in datasheet section > Hide/Unhide

 

[Gavx]

Thanks. I think I did something like that but not in the correct place. thanks again