diff --git a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
index 23620a4bd7..cc1e8a98f2 100644
--- a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
+++ b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
@@ -189,16 +189,6 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
     for (auto customButton : customButtons)
         addButton(customButton.label, customButton.id, customButton.role);
 
-
-    // QMessageDialog's logic for adding a fallback OK button if no other buttons
-    // are added depends on QMessageBox::showEvent(), which is too late when
-    // native dialogs are in use. To ensure there's always an OK button with a tag
-    // we recognize we add it explicitly here as a fallback.
-    if (!m_alert.buttons.count) {
-        addButton(platformTheme->standardButtonText(StandardButton::Ok),
-            StandardButton::Ok, ButtonRole::AcceptRole);
-    }
-
     if (auto checkBoxLabel = options()->checkBoxLabel(); !checkBoxLabel.isNull()) {
         checkBoxLabel = QPlatformTheme::removeMnemonics(checkBoxLabel);
         m_alert.suppressionButton.title = checkBoxLabel.toNSString();
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index ca7af90c15..ef1d8b04aa 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -1661,6 +1661,11 @@ void QMessageBoxPrivate::setVisible(bool visible)
 {
     Q_Q(QMessageBox);
 
+    // Last minute setup
+    if (autoAddOkButton)
+        q->addButton(QMessageBox::Ok);
+    detectEscapeButton();
+
     if (canBeNativeDialog())
         setNativeDialogVisible(visible);
 
@@ -1705,13 +1710,7 @@ QMessageBox::ButtonRole QMessageBox::buttonRole(QAbstractButton *button) const
 void QMessageBox::showEvent(QShowEvent *e)
 {
     Q_D(QMessageBox);
-    if (d->autoAddOkButton) {
-        addButton(Ok);
-    }
-    if (d->detailsButton)
-        addButton(d->detailsButton, QMessageBox::ActionRole);
     d->clickedButton = nullptr;
-    d->detectEscapeButton();
     d->updateSize();
 
 #if QT_CONFIG(accessibility)