diff --git a/src/headless/public/Terminal.ts b/src/headless/public/Terminal.ts
index 738570c9..c8d6fe7c 100644
--- a/src/headless/public/Terminal.ts
+++ b/src/headless/public/Terminal.ts
@@ -124,6 +124,7 @@ export class Terminal extends Disposable implements ITerminalApi {
       originMode: m.origin,
       reverseWraparoundMode: m.reverseWraparound,
       sendFocusMode: m.sendFocus,
+      synchronizedOutputMode: m.synchronizedOutput,
       wraparoundMode: m.wraparound
     };
   }