ref #8107 getFieldGroup() returns Optional to avoid NPEs and logging errors before rethrowing as PopupEditorException
fix #7899 orthographic variant and corrections implemented in taxon name popup editor
fix #7588 updating buttons on setDataSource
ref #7361 creating new icon 'create-new' & introducing ButtonFactory for harmonization of button creation
ref #7364 fixing readonly state of NameRelationField
ref #7364 validation section implemented in TaxonNameEditor