"Area already set" error when saving theme configuration in Admin

This article provides a patch for the known Magento Commerce (Cloud) 2.2.4 issue related to getting the "Area is already set" error message when trying to set a theme for the Default Store View in the Magento Admin.

Issue

You get the "Something went wrong while saving this configuration: Area is already set" error message when trying to set a theme for the Default Store View.

Steps to reproduce:

1. Log in to Magento Admin.
2. Navigate to Content>Design>Configuration.
3. Set the configuration scope to Default Store View.
4. Change the theme in the Applied Theme drop-down. For example, from Magento Luma to Magento Blank.
5. Click Save Configuration.

Expected result:
The selected theme is applied for the default store view.

Actual result:
Theme is not applied, the "Something went wrong while saving this configuration: Area is already set" error message is displayed.

Patch

The patch is attached to this article. To download it, click the following link or scroll down to the end of the article and click the attached file:

Download MDVA-11106_EE_2.2.4_v1.composer.patch

Compatible Magento versions:

The patch was created for:

• Magento Commerce (Cloud) 2.2.4

The patch is also compatible (but might not solve the issue) with the following Magento versions and editions:

• Magento Commerce (Cloud) 2.0.X
• Magento Commerce (Cloud) 2.1.X
• Magento Commerce (Cloud) from 2.2.0 to 2.2.5
• Magento Commerce 2.0.X
• Magento Commerce 2.1.X
• Magento Commerce from 2.2.0 to 2.2.5

How to apply the patch

We strongly recommend applying and testing the patch on the Integration/Staging environment, before applying it Production. We also recommend to have a recent backup before any manipulations.

How to apply this patch for Magento Commerce (Cloud) 

(replace the patch name with a particular one)

1. If you do not have a directory named m2-hotfixes in the project root, please create one.
2. Copy the MDVA-11106_EE_2.2.4_v1.composer.patch file(s) to the m2-hotfixes directory.

3. Add, commit, and push your code changes:

   git add -A && git commit -m "Apply MDVA-11106_EE_2.2.4_v1 patch" && git push origin

How to apply this patch for Magento Commerce

1. Upload the patch to your Magento root directory.
2. Run the following SSH command:

   patch -p1 < MDVA-11106_EE_2.2.4_v1.composer.patch

   (If the above command does not work, try using -p2 instead of -p1)
3. For the changes to be reflected, refresh the cache in the Admin under System > Cache Management.

Useful links

Apply custom patches to Magento Commerce (Cloud)

Attached Files