Workflow > Display Sales Order number in Show message popup whenever an item has been received

When receiving an item (Item Receipts Page) from a special order, only the Purchase Order ID is exposed in the workflow by using the {createdfrom.createdfrom} formula to in the text area of the Show Message action.
To be able to display the Sales Order number from where the item has been created, a custom field is necessary to achieve this requirement.

Create the Custom Field:  
- Navigate to Customization > Lists, Records, & Fields > Transaction Body Fields > New
- Type any name for the Label Field. (Example: "Related to SO")
- Set Type to Free-Form Text
- Uncheck Store Value checkbox
- On the Applies To subtab, check the Item Receipt checkbox
- On the Display subtab, Subtab field is set to Main and Display Type is set to Inline Text
- On Validation & Defaulting subtab, in the Default Value field, type in {createdfrom.createdfrom} then check the Formula checkbox.
- Save and take note of the custom field ID

Create the Workflow:
- Navigate to Customization > Workflow >Workflows > New
- Set a Name for the Workflow
- Set Record Type to "Transaction" and Subtypes to "Item Receipt"
- Released Status set to Released or Testing
- Initiation is set to Event Based
- Trigger Type is set to Before Record Load
- Save the Workflow
- Create a New State
- On the New State, click the New Action button
- Click the Show Message action and it will redirect to the Workflow action page
- On the Workflow Action page, set Trigger On to Before User Edit
- On the Text area box under the Parameters section, type the custom field ID that has been generated earlier enclosed in curly braces (ex:{custombody999})
- Save Workflow action and test by creating a Sales order using a Special Order Item.