The Ragic system will not allow you to delete a field which is referenced by other sheets.
Similarly, when attempting to delete a sheet which contains a field referenced by other sheets, the Ragic system will stop you from doing so.
This is because, if you delete a field referenced by other sheets, one or more fields will lose their reference source. For example, if you link the “Customer” sheet from the “Sales Order” sheet, and set the “Customer ID” field as the linked field, when you select the “Customer ID” field in the “Sales Order” sheet, Ragic can automatically load the customer's information. If you delete the “Customer ID” field in the “Customer” sheets afterwards, the link and load feature will not work.
If you still want to delete this kind of field, we suggest you to unlink those fields before deleting.