diff --git a/lcl/dialogs.pp b/lcl/dialogs.pp
index cad19e744b..d6adc7c1e7 100644
--- a/lcl/dialogs.pp
+++ b/lcl/dialogs.pp
@@ -544,7 +544,7 @@ type
     tfShowMarqueeProgressBar, tfCallbackTimer,
     tfPositionRelativeToWindow, tfRtlLayout,
     tfNoDefaultRadioButton, tfCanBeMinimized,
-    tfForceNonNative);
+    tfForceNonNative, tfEmulateClassicStyle);
   TTaskDialogFlags = set of TTaskDialogFlag;
 
   TTaskDialogCommonButton = (tcbOk, tcbYes, tcbNo, tcbCancel, tcbRetry, tcbClose);
diff --git a/lcl/include/taskdialog.inc b/lcl/include/taskdialog.inc
index 021944bbd7..2ce5a97571 100644
--- a/lcl/include/taskdialog.inc
+++ b/lcl/include/taskdialog.inc
@@ -240,7 +240,7 @@ begin
   TaskDlg.Verify := VerificationText;
 
   ButtonID := TaskDlg.Execute(TD_COMMONBUTTONS(CommonButtons), DefBtn, TD_FLAGS(Flags), TF_DIALOGICON(MainIcon), TF_FOOTERICON(FooterIcon),
-    DefRB, FWidth, ParentWnd, tfForceNonNative in Flags, False, @DoOnButtonClickedHandler);
+    DefRB, FWidth, ParentWnd, tfForceNonNative in Flags, tfEmulateClassicStyle in Flags, @DoOnButtonClickedHandler);
   Result := ButtonID>=0;
   FModalResult := ButtonIDToModalResult(ButtonID);