M 2.3.0: Can't Access Design Configuration - Global View page. Getting Error "Uncaught ReferenceError: Base64 is not defined."

Question

After updating to Magento 2.3.0 from 2.2.6, I am unable to access the Design Configuration - Global View page. When I open the page, the GIF Spinner keeps rotating, but the page never fully loads.

Checking the console log, I can see the following error:

VM1667:2 Uncaught ReferenceError: Base64 is not defined
at UiClass.processFile (eval at require.load (static.min.js:9), <anonymous>:2:1857)
at Array.map (<anonymous>)
at UiClass.setInitialValue (eval at require.load (static.min.js:9), <anonymous>:2:1150)
at UiClass.initialize (eval at require.load (static.min.js:9), <anonymous>:2:1202)
at UiClass.eval [as initialize] (eval at require.load (static.min.js:9), <anonymous>:4:186)
at new UiClass (eval at require.load (static.min.js:9), <anonymous>:4:16)
at Object.initComponent (eval at require.load (static.min.js:9), <anonymous>:9:51)
at fire (eval at require.load (static.min.js:9), <anonymous>:213:223)
at Object.fireWith [as resolveWith] (eval at require.load (static.min.js:9), <anonymous>:219:181)
at Object.deferred.(/adMin/theme/design_config/edit/scope/default/key/9b7ba6c60a1a953e7c9f503841ea105378552041ca0bbd78fa9e7a700aa732b2/anonymous function) (eval at require.load (https://pub/static/version1545029869/adminhtml/Magento/backend/en_US/mage/requirejs/static.min.js:9:216), <anonymous>:221:56)

Answer 1

This is what worked for me: https://github.com/magento/magento2/issues/19549#issuecomment-447327672

To test, I first made the edit only in the file 'vendor/magento/module-theme/view/adminhtml/ui_component/design_config_form.xml', and it worked!

Seems to be a bug, which will be patched in Magento 2.3.1 release.

Answer 2

Other vendor(moduel-catalog , module-email , module-ui) don't override when it required then after change

To test, I first made the edit only in the file 'vendor/magento/module-theme/view/adminhtml/ui_component/design_config_form.xml',

find formElement="fileUploader" and replace with formElement="imageUploader"

and it worked!

Seems to be a bug, which will be patched in Magento 2.3.1 and 2.3.0 release.