CouponAdmin not showing action to generate coupons

[wernerkrauss]

In DiscountModelAdmin's getEditForm() I changed this:

        if ($grid = $form->Fields()->fieldByName($this->sanitiseClassName(OrderCoupon::class))) {
            $grid->getConfig()
                ->addComponent(
                    $link = new GridField_LinkComponent('Generate Multiple Coupons', $this->Link(). '/generatecoupons'),
                    GridFieldExportButton::class
                );
            $link->addExtraClass('ss-ui-action-constructive btn btn-primary');
        }

It fixes a lot, but I didn't go too much into detail. It's still not shown inside the GridfieldButtonRow above but underneath it.