Change behavior of initialize fields to create protected properties, rather than private

In PhpStorm 2017.3.2 you can change fields default visibility in the next way: Project Settings (Ctrl + Alt + S) => Editor => Code Style => PHP => Code Generation tab => Fields Default Visibility. Works fine for me.

I've searched around for answer to this question.

What I've found out is that you cannot modify behavior of this function without modifying PHP plugin. This plugin is in fact responsible for behavior of Initialize fields function.

Here is the example of edit initialize fields option. But it's read only: