If you have added new fields to a sheet generated from a subtable, or have added a reference subtable to a sheet and would like to add new fields from the parent sheet, you can use the link fields from parent sheets option to link the new fields.
Optionally, you can also add independent fields that belong to the parent sheet for display purposes by using this linking tool.
On Sales Order sheet, you initially created a new sheet from sales items subtable, and added a new subtable field on the Sales Order sheet that you would like to add to the new sheet created from this subtable as well. You can achieve your goal by using the link fields from parent sheet option.
If you would like to display other information related to the Sales Order on the new sheet created from subtable, such as the Sales Order Date or Order Status, then you can add these fields by using this linking tool. These newly added fields will automatically be set as read only by default. As these new fields share field ids with their corresponding fields on the parent sheet, they will display accurate information in real-time, but can be only used for display purposes.
To use this type of linking, navigate to the Design Mode through the Change Design button. Click on Form Tools. You'll see the available parent sheets as options listed under Link fields from parent sheets, in the Sheet Linking Tools category.
When you click on the sheet name, a pop-up window will list all the available fields that can be added to your child sheet. You can drag and drop any of these listed available fields into your database design.
The available fields with a red border are subtable fields linked with the current sheet. The fields with a blue border are regular fields that belong to the parent sheet, which should be used only for display purposes on the current sheet.
Don't forget to save your design before exiting the design mode.