Child-Child-Theme Magento 2.1.3

Question

I am setting up a magento multistore.

I want to have one main child theme with layout and CSS changes, that every site should have.

From this theme my site-specific child themes should inherit.

I have already set up successfully simple child themes but the above constellation does not work. The changes from "main child theme" are not visible.

Can anybody tell me if this is possible?

Main-Child inherits from Luma
Site1-Child inherits from Main-Child

EDIT: Changes made in Site1-Child are visible on frontend (for example removing layout blocks). But changes made in Main-Child are not visible. Both Themes have static files. It looks like Site1-Child does not correctly inherit from Main-Child. If I assign Main-Child as actual theme for Site1, the changes are visible.

Answer 1

do you have any static files in the child theme?

Currently, the whole theme does not get deployed if it does not have any static files.

https://github.com/magento/magento2/issues/7569

Answer 2

You just need to create and to change that file below in your child themes, depending for your relative parent themes.

File theme.xml

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
    <title>Your Theme</title>
    <parent>Package/theme</parent>
    <media>
        <preview_image>media/preview.png</preview_image>
    </media>
</theme>

Answer 3

This is not a full answer but the app didn't show a comment only option

I've been trying to set up a similar structure. For all I've researched and tried (very little documentation on this) you can only have one level of "childness".

I was trying: RWD > MyMain > AChild

Couldn't get it to work. XML directives got all messed up.

Please, anyone who knows the above is wrong, pitch in.