diff --git a/src/browser/Terminal.ts b/src/browser/Terminal.ts
index d69e5d6f..31ef1287 100644
--- a/src/browser/Terminal.ts
+++ b/src/browser/Terminal.ts
@@ -1016,7 +1016,7 @@ export class Terminal extends CoreTerminal implements ITerminal {
   }
 
   public registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined {
-    return this._decorationService!.registerDecoration(decorationOptions);
+    return this._decorationService.registerDecoration(decorationOptions);
   }
 
   /**