Today we've updated from version 2.0.6 to 2.1.2, it was everything but flawless. But I've managed to fix all te problems except one:
When editing a product I receive this error:
Exception #0 (InvalidArgumentException): Magento\Catalog\Block\Adminhtml\Product\Helper\Form\Gallery doesn'n extend \Magento\Framework\Data\Form\Element\AbstractElement
Does anyone know how to fix this problem?
