Multiple Category Sources Field I want to utilise the Category field type but with the ability to choose from multiple category sources (as with Entries).

I noted in cms/src/fields/Categories.php that $this-&gt;allowMultipleSources is set to false. What is the simplest way of changing this to true without changing the source file?

Can I create a custom field that essentially just extends the original Category field but with $this-&gt;allowMultipleSources set to true?
Isnt this possible with the modifyCategorySources hook?

-> https://docs.craftcms.com/v3/extend/updating-plugins.html#modifyentrysources-modifycategorysources-modifyassetsources-modifyusersources

I'm assuming you are using C3 by the namespace you mentioned. Correct me if this is wrong :).