1 files changed, 10 insertions, 6 deletions
diff --git a/src/plugins/platforms/windows/qwindowswindowclassregistry.cpp b/src/plugins/platforms/windows/qwindowswindowclassregistry.cpp
index e367350d55e..19694eab330 100644
--- a/src/plugins/platforms/windows/qwindowswindowclassregistry.cpp
+++ b/src/plugins/platforms/windows/qwindowswindowclassregistry.cpp
@@ -59,6 +59,9 @@ QString QWindowsWindowClassRegistry::registerWindowClass(const QWindowsWindowCla
 {
     QString className = description.name;
 
+    if (description.shouldAddPrefix)
+        className = classNamePrefix() + className;
+
     // since multiple Qt versions can be used in one process
     // each one has to have window class names with a unique name
     // The first instance gets the unmodified name; if the class
@@ -107,13 +110,13 @@ QString QWindowsWindowClassRegistry::registerWindowClass(const QWindowsWindowCla
     wc.lpszClassName = reinterpret_cast<LPCWSTR>(className.utf16());
     ATOM atom = RegisterClassEx(&wc);
     if (!atom)
-        qErrnoWarning("QApplication::regClass: Registering window class '%s' failed.",
-            qPrintable(className));
+        qCWarning(lcQpaWindowClass) << "Failed to register window class" << className
+            << "(" << qt_error_string(-1) << ")";
 
     m_registeredWindowClassNames.insert(className);
-    qCDebug(lcQpaWindowClass).nospace() << __FUNCTION__ << ' ' << className
-        << " style=0x" << Qt::hex << description.style << Qt::dec
-        << " brush=" << description.brush << " icon=" << description.hasIcon << " atom=" << atom;
+
+    qCDebug(lcQpaWindowClass).nospace() << __FUNCTION__ << ' ' << className << ' ' << description << " atom=" << atom;
+
     return className;
 }
 
@@ -133,7 +136,8 @@ void QWindowsWindowClassRegistry::unregisterWindowClasses()
 
     for (const QString &name : std::as_const(m_registeredWindowClassNames)) {
         if (!UnregisterClass(reinterpret_cast<LPCWSTR>(name.utf16()), appInstance) && QWindowsContext::verbose)
-            qErrnoWarning("UnregisterClass failed for '%s'", qPrintable(name));
+            qCWarning(lcQpaWindowClass) << "Failed to unregister window class" << name
+                << "(" << qt_error_string(-1) << ")";
     }
     m_registeredWindowClassNames.clear();
 }