Two language interfaces and extension installation.

Recently one of our clients who has Dreamweaver CC 2017, bought an extension, he installed it using Adobe Cloud Panel and synchronization. BUT the extension didn't appear in Dreamweaver. He has French Dreamweaver localization. I believe this is the problem and extension has been installed into en_US folder and not into fr_FR. Why this happen?

I advised client to copy/paste everything form en_US folder into fr_FR, but client told that this is very complicated and asked Adobe for a refund. So I've lost one purchase because of troubles with installation process.

What can be done in order to force extension to install into Dreamweaver necessary (main) localization. I mean like in this example, to force extensions to install into fr_FR and not into en_US folder.

I've already contacted Adobe Support but everything I got: "The issue you have reported is a known issue and we are working on it. It might be resolved by the next release."  It was many patches and releases ago...

What is the best way out when extension is installed into different config folder? Copy everything from one language into different but what about Dreamweaver interface?!