Magento 2 Custom Admin Theme

Question

I am creating a custom admin theme for Magento 2 and followed the Magento 2 documentation. My problem is that all styles are removed on the backend and I do not understand why it is not defaulting to Magento/backend theme parent. Here is my theme.xml

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

Here is my module.xml:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
<module name="Vendor_MenuItem" setup_version="1.0.0" />
</config>

and my added di.xml to my module:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">

<!-- Admin theme. Start -->
<type name="Magento\Theme\Model\View\Design">
    <arguments>
        <argument name="themes" xsi:type="array">
            <item name="adminhtml" xsi:type="string">Vendor/MyTheme</item> <!-- Example: "Magento/backend" -->
        </argument>
    </arguments>
</type>
<!-- Admin theme. End -->
</config>

The logo works just fine but I lost all previous styling and all adminhtml looks like basic html. Any insight would be appreciated.

Answer 1

Try editing your module.xml file to this:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_MenuItem" setup_version="1.0.0">
        <sequence>
            <module name="Magento_Theme"/>
        </sequence>
    </module>
</config>

As per the Magento 2 Docs you need to load Magento_Theme before your module.