Text, input/output field and icon cannot all be missing at the same time

What causes this issue?

You are editing a text field or an input/output field.
If you are editing a field text, the text is blank and no icon has been
specified.
If you are editing an input/output field, the template is blank and no
icon has been specified.

System Response

The system interprets this as a blank screen element which it cannot
accept.

How to fix this error?

If you are editing a field text, at least specify a text or define an
icon.
If you are editing an input/output field, at least specify a template,
define a length (in order to create a template of this length) or
define an icon by setting the checkbox "With icon".

Error message extract from SAP system. Copyright SAP SE.