diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index c8eaded38d..cdc0b24464 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1936,7 +1936,10 @@ void QWindowsWindow::getSizeHints(MINMAXINFO *mmi) const
             && (m_data.flags & Qt::FramelessWindowHint)) {
         // This block fixes QTBUG-8361: Frameless windows shouldn't cover the
         // taskbar when maximized
-        if (const QScreen *screen = effectiveScreen(window())) {
+        const QScreen *screen = effectiveScreen(window());
+
+        // Documentation of MINMAXINFO states that it will only work for the primary screen
+        if (screen && screen == QGuiApplication::primaryScreen()) {
             mmi->ptMaxSize.y = screen->availableGeometry().height();
 
             // Width, because you can have the taskbar on the sides too.
@@ -1945,8 +1948,8 @@ void QWindowsWindow::getSizeHints(MINMAXINFO *mmi) const
             // If you have the taskbar on top, or on the left you don't want it at (0,0):
             mmi->ptMaxPosition.x = screen->availableGeometry().x();
             mmi->ptMaxPosition.y = screen->availableGeometry().y();
-        } else {
-            qWarning() << "Invalid screen";
+        } else if (!screen){
+            qWarning() << "effectiveScreen() returned a null screen";
         }
     }