Whether a FormContext change alters anything a section derives from a field.
BaseFormComponent.formContext is a getter that builds a fresh object on every access, so a
field's [FormContext] input changes identity on every pass and ngOnChanges fires every pass.
Notifying the section each time would dirty the panel and the rail after they were checked and
force an extra refresh per tick with nothing changed. Only these members feed the section's
counts: showValidation / validationRevision / validationErrors (whether a field paints an
error) and showEmptyFields (whether an empty read-only field is hidden).
Whether a
FormContextchange alters anything a section derives from a field.BaseFormComponent.formContextis a getter that builds a fresh object on every access, so a field's[FormContext]input changes identity on every pass andngOnChangesfires every pass. Notifying the section each time would dirty the panel and the rail after they were checked and force an extra refresh per tick with nothing changed. Only these members feed the section's counts:showValidation/validationRevision/validationErrors(whether a field paints an error) andshowEmptyFields(whether an empty read-only field is hidden).