Symptoms
Users are unable to uncheck Work Notes field in Form Personalization from the header menu popup and set it as a user preference so that Work Notes are not displayed on the form
Release
Any release
Cause
Currently by system design to ensure Work Notes field is always available on the form as long as it is part of the Form Configuration
Resolution
Please note that the Work Note field check box in Personalize Form is grayed out at the base code level and is by design. It is not possible to edit this checkbox when grayed out by the system.
Here is more information in the docs link below regarding this:
"Some checkboxes are gray and selected. These check boxes indicate fields that cannot be hidden because they are required or are already hidden by UI policies or client scripts"