diff --git a/kcms/desktoptheme/kcm.cpp b/kcms/desktoptheme/kcm.cpp
--- a/kcms/desktoptheme/kcm.cpp
+++ b/kcms/desktoptheme/kcm.cpp
@@ -52,10 +52,6 @@
     , m_defaultTheme(new Plasma::Theme(this))
     , m_haveThemeExplorerInstalled(false)
 {
-    //This flag seems to be needed in order for QQuickWidget to work
-    //see https://bugreports.qt-project.org/browse/QTBUG-40765
-    //also, it seems to work only if set in the kcm, not in the systemsettings' main
-    qApp->setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
     qmlRegisterType<QStandardItemModel>();
 
     KAboutData* about = new KAboutData(QStringLiteral("kcm_desktoptheme"), i18n("Plasma Style"),
diff --git a/kcms/fonts/fonts.cpp b/kcms/fonts/fonts.cpp
--- a/kcms/fonts/fonts.cpp
+++ b/kcms/fonts/fonts.cpp
@@ -468,7 +468,6 @@
     : KQuickAddons::ConfigModule(parent, args)
     , m_fontAASettings(new FontAASettings(this))
 {
-    qApp->setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
     KAboutData* about = new KAboutData("kcm_fonts", i18n("Fonts"),
                                        "0.1", QString(), KAboutLicense::LGPL);
     about->addAuthor(i18n("Antonis Tsiapaliokas"), QString(), "antonis.tsiapaliokas@kde.org");
diff --git a/kcms/lookandfeel/kcm.cpp b/kcms/lookandfeel/kcm.cpp
--- a/kcms/lookandfeel/kcm.cpp
+++ b/kcms/lookandfeel/kcm.cpp
@@ -67,10 +67,6 @@
     , m_resetDefaultLayout(false)
     , m_applyWindowDecoration(true)
 {
-    //This flag seems to be needed in order for QQuickWidget to work
-    //see https://bugreports.qt-project.org/browse/QTBUG-40765
-    //also, it seems to work only if set in the kcm, not in the systemsettings' main
-    qApp->setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
     qmlRegisterType<QStandardItemModel>();
     qmlRegisterType<KCMLookandFeel>();
     KAboutData* about = new KAboutData(QStringLiteral("kcm_lookandfeel"), i18n("Global Theme"),