NSC | Using Formulas and Sourcing on Custom Fields
When utilizing Formulas on creating Custom Fields, users often report that the Custom Field displays a blank value. One common reason causing this is that the Store Value checkbox remains enabled.
If Validation & Defaulting and Sourcing & Filtering feature will be used in Custom Fields, it is best to uncheck the Store Value checkbox to ensure that the Custom Field will use the settings applied in the said subtabs.
Note: Be careful in disabling the Store Value checkbox in existing Custom Fields since it will remove all the existing values in those Custom Fields.
In the example below, the Custom Field will display the Title of the Opportunity record. Notice that the Store Value Checkbox is unchecked.