diff --git a/src/stc/scintilla/src/Document.h b/src/stc/scintilla/src/Document.h
index effdd5fe55..d74678375c 100644
--- a/src/stc/scintilla/src/Document.h
+++ b/src/stc/scintilla/src/Document.h
@@ -191,6 +191,9 @@ public:
 		bool operator==(const WatcherWithUserData &other) const {
 			return (watcher == other.watcher) && (userData == other.userData);
 		}
+		bool operator!=(const WatcherWithUserData &other) const {
+			return (watcher != other.watcher) || (userData != other.userData);
+		}
 	};
 
 private: