diff --git a/src/ioslaves/http/kcookiejar/kcookieserver.cpp b/src/ioslaves/http/kcookiejar/kcookieserver.cpp
--- a/src/ioslaves/http/kcookiejar/kcookieserver.cpp
+++ b/src/ioslaves/http/kcookiejar/kcookieserver.cpp
@@ -236,7 +236,8 @@
                                     mCookieJar->preferredDefaultPolicy(),
                                     mCookieJar->showCookieDetails());
     if (windowId > 0) {
-        KWindowSystem::setMainWindow(kw, windowId);
+        kw->setAttribute(Qt::WA_NativeWindow, true);
+        KWindowSystem::setMainWindow(kw->windowHandle(), windowId);
     }
 
     KCookieAdvice userAdvice = kw->advice(mCookieJar, currentCookie);
diff --git a/src/ioslaves/http/kcookiejar/kcookiewin.cpp b/src/ioslaves/http/kcookiejar/kcookiewin.cpp
--- a/src/ioslaves/http/kcookiejar/kcookiewin.cpp
+++ b/src/ioslaves/http/kcookiejar/kcookiewin.cpp
@@ -67,7 +67,8 @@
     setWindowIcon(QIcon::fromTheme(QStringLiteral("preferences-web-browser-cookies")));
     // all cookies in the list should have the same window at this time, so let's take the first
     if (!cookieList.first().windowIds().isEmpty()) {
-        KWindowSystem::setMainWindow(this, cookieList.first().windowIds().first());
+        setAttribute(Qt::WA_NativeWindow, true);
+        KWindowSystem::setMainWindow(windowHandle(), cookieList.first().windowIds().first());
     } else {
         // No window associated... make sure the user notices our dialog.
         KWindowSystem::setState(winId(), NET::KeepAbove);
diff --git a/src/kpasswdserver/kpasswdserver.cpp b/src/kpasswdserver/kpasswdserver.cpp
--- a/src/kpasswdserver/kpasswdserver.cpp
+++ b/src/kpasswdserver/kpasswdserver.cpp
@@ -575,11 +575,8 @@
                                            QStringList(), QString(), nullptr,
                                            (KMessageBox::Notify | KMessageBox::NoExec));
 
-        #ifndef Q_WS_WIN
-            KWindowSystem::setMainWindow(dlg, request->windowId);
-        #else
-            KWindowSystem::setMainWindow(dlg, (HWND)(long)request->windowId);
-        #endif
+            dlg->setAttribute(Qt::WA_NativeWindow, true);
+            KWindowSystem::setMainWindow(dlg->windowHandle(), request->windowId);
 
             qCDebug(category) << "Calling open on retry dialog" << dlg;
             m_authRetryInProgress.insert(dlg, request.take());
@@ -850,11 +847,7 @@
 #endif
 
     // instantiate dialog
-#ifndef Q_WS_WIN
     qCDebug(category) << "Widget for" << request->windowId << QWidget::find(request->windowId);
-#else
-    qCDebug(category) << "Widget for" << request->windowId << QWidget::find((HWND)request->windowId);
-#endif
 
     KPasswordDialog* dlg = new KPasswordDialog(nullptr, dialogFlags);
     connect(dlg, &QDialog::finished, this, &KPasswdServer::passwordDialogDone);
@@ -888,11 +881,8 @@
         dlg->setAnonymousMode(info.getExtraField(AUTHINFO_EXTRAFIELD_ANONYMOUS).toBool());
 
 #ifndef Q_OS_MACOS
-#ifndef Q_WS_WIN
-    KWindowSystem::setMainWindow(dlg, request->windowId);
-#else
-    KWindowSystem::setMainWindow(dlg, (HWND)request->windowId);
-#endif
+    dlg->setAttribute(Qt::WA_NativeWindow, true);
+    KWindowSystem::setMainWindow(dlg->windowHandle(), request->windowId);
 #else
     KWindowSystem::forceActiveWindow(dlg->winId(), 0);
 #endif