Tax Code field becomes blank on Sales Order when shipping address is changed

Answer/Solution:
When the shipping address is changed without clicking the Add button for the item, the tax code will be emptied because the item information has not yet been sent to the system. The system will check the applicable tax on the item based on the new address. Since the item has not yet been added, the system would not detect any item and the tax code would therefore be set to blank. Take note that all the fields that are dependent on the tax code will also be set to blank.

Always make sure to click Add button after selecting an item.

Steps (Using not yet upgraded Standard Sales Order):
1. Navigate to Transactions > Sales > Enter Sales Orders
2. Select a customer
3. Click Items subtab
4. Select an item > Make sure that there are entries for Rate, Amount, Tax Code, Tax Rate, Tax Amt, and Gross Amt fields
5. Click Add button > Click Address subtab
6. Change the shipping address by setting a different one on Ship To Select field
7. Return to Items subtab > Note that Tax Code, Tax Rate, Tax Amt, and Gross Amt fields are still populated