diff --git a/src/core/utils_mac.mm b/src/core/utils_mac.mm
index a17c5b89..40956cad 100644
--- a/src/core/utils_mac.mm
+++ b/src/core/utils_mac.mm
@@ -247,6 +247,7 @@ explicit NSWindowProxy(QWindow *qtWindow, NSWindow *macWindow, QObject *parent =
     {
         instances.remove(nswindow);
         if (instances.count() <= 0) {
+            restoreImplementations();
             windowClass = nil;
         }
         nswindow = nil;