FormHandler add does not show dropdowns while FormHandler edit does

Raised by @sindhura.ch

When using a select for specific columns (see code below):

      columns: [
        { name: '*' },
        {
          name: 'user_designation',
          editable: {
            input: 'select',
            options: ['ACMO', 'CDO']
          }
        },
        { name: 'user_password', hide: true },
        { name: 'actions', template: $('#action-template').html() }
      ]

... the dropdown is visible when we click Edit but not when we click Add. See screenshots below.