⏫ Forwardport of #11765 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/11765.patch (created by @bentideswell) based on commit(s): 1. 4d79191
magento · Jan 23, 2018 · 6d3d70a · 6d3d70a
1 parent 8e77e2f
commit 6d3d70a
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/lib/internal/Magento/Framework/View/Layout/etc/elements.xsd b/lib/internal/Magento/Framework/View/Layout/etc/elements.xsd
@@ -138,7 +138,7 @@
 
     <xs:simpleType name="blockClassType">
         <xs:restriction base="xs:string">
-            <xs:pattern value="[A-Z][a-zA-Z\d]*(\\[A-Z][a-zA-Z\d]*)*"/>
+            <xs:pattern value="[A-Z][_a-zA-Z\d]*(\\[A-Z][_a-zA-Z\d]*)*"/>
         </xs:restriction>
     </xs:simpleType>