When a PO is linked to a Job, the Job Type setup controls whether or not a GL Account is available on the Expense Tab.
Purchase Order
Create a New Purchase Order and select a Job Number.
Go to the Expense Tab and select the drop-down menu for the GL Account.
If the GL Account needed is not listed, and you are not able to access the GL Account List button, this is controlled by the Job Type Setup for the Job linked to the Purchase Order.


SedonaSetup – Job Types
Go to SedonaSetup and select Job Types.
Select the Job Type for the Job linked to the Purchase Order.
Select the Accounts Tab.
The GL Accounts listed in that Section will be the only ones available in the GL Account drop-down menu on the Purchase Order, and this will prevent you from being able to access the GL Account List button on a PO.

New GL Accounts can be added to the Account List in the Job Type, which will then show in the GL Account drop-down menu on the PO.
If you remove each of the GL Accounts listed under the Accounts Tab in the Job Type, the GL Account List Button will become visible, and you can select the GL Account needed.
If there are still GL Accounts listed in the drop-down menu, these are entered under the Vendor Information > GL Accounts Tab.