Fix for #12977

extensions/html/client/src/htmlMain.ts

@@ -77,4 +77,19 @@ export function activate(context: ExtensionContext) {
 			}
 		],
 	});
+
+	languages.setLanguageConfiguration('razor', {
+		wordPattern: /("(?:[^\\\"]*(?:\\.)?)*"?)|('(?:[^\\\']*(?:\\.)?)*'?)|[^\s<>={}\[\],]+/,
+		onEnterRules:[
+			{
+				beforeText: new RegExp(`<(?!(?:${EMPTY_ELEMENTS.join('|')}))([_:\\w][_:\\w-.\\d]*)([^/>]*(?!/)>)[^<]*$`, 'i'),
+				afterText: /^<\/([_:\w][_:\w-.\d]*)\s*>$/i,
+				action: { indentAction: IndentAction.IndentOutdent }
+			},
+			{
+				beforeText: new RegExp(`<(?!(?:${EMPTY_ELEMENTS.join('|')}))(\\w[\\w\\d]*)([^/>]*(?!/)>)[^<]*$`, 'i'),
+				action: { indentAction: IndentAction.Indent }
+			}
+		],
+	});
 }
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