A custom field, named "Dev estimate", which is based on the "Original estimate" type of field, was assigned to the "story" issue. It was also associated with the "Story [create or Edit]" screen (field is marked with v).
_In spite of the above_, when opening a story for edit (or creating a new story) - this field is not shown.
Running the 'Admin helper' plugin to check "Where is my field" leads to a positive result (3 green v marks) - "The 'Dev Estimate' field should be present on the form you are viewing".
So why can't I see this field? what other reason can prevent it from being visible during edit?