Implement "Use system value" in custom module

Question

In the magento backend under Stores -> Configuration some of the fields have the "Use system value" checkbox next to them and some don't have it.

Checking the checkbox "restores" the field to the default value (which is defined in module's config.xml file).

How can I implement this "Use system value" checkbox in a custom module? Is it possible?

When I add custom config fields to my module, they don't have this "Use system value" checkbox.

Answer 1

canRestore property

etc/adminhtml/system.xml

<field id="some" translate="label" type="text" sortOrder="30" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
    ...
</field>