diff --git a/src/kwindoweffects.h b/src/kwindoweffects.h
--- a/src/kwindoweffects.h
+++ b/src/kwindoweffects.h
@@ -20,11 +20,7 @@
 
 #include "kwindowsystem_export.h"
 
-#ifndef KWINDOWSYSTEM_NO_QWIDGET
-#include <QWidget> // for WId, etc.
-#else
-class QWidget;
-#endif
+#include <QWidgetList> // for WId, etc.
 
 #include <QRegion>
 #include <netwm_def.h>
diff --git a/src/platforms/xcb/kselectionowner.cpp b/src/platforms/xcb/kselectionowner.cpp
--- a/src/platforms/xcb/kselectionowner.cpp
+++ b/src/platforms/xcb/kselectionowner.cpp
@@ -34,7 +34,6 @@
 #include <QAbstractNativeEventFilter>
 
 #include <qx11info_x11.h>
-#include <qwidget.h>
 
 static xcb_window_t get_selection_owner(xcb_connection_t *c, xcb_atom_t selection)
 {
diff --git a/src/platforms/xcb/kwindowsystem.cpp b/src/platforms/xcb/kwindowsystem.cpp
--- a/src/platforms/xcb/kwindowsystem.cpp
+++ b/src/platforms/xcb/kwindowsystem.cpp
@@ -21,11 +21,11 @@
 #include "kwindowsystem.h"
 #include "kwindowsystem_p_x11.h"
 
-#include <QDebug>
 #include <kxerrorhandler_p.h>
-#include <kxutils_p.h>
 #include <fixx11h.h>
+#include <kxutils_p.h>
 
+#include <QDebug>
 #include <QBitmap>
 #include <QGuiApplication>
 #include <QIcon>
diff --git a/src/platforms/xcb/netwm.h b/src/platforms/xcb/netwm.h
--- a/src/platforms/xcb/netwm.h
+++ b/src/platforms/xcb/netwm.h
@@ -31,13 +31,10 @@
 #include <config-kwindowsystem.h>
 #if KWINDOWSYSTEM_HAVE_X11
 #include <xcb/xcb.h>
+#include <vector>
 
 #include "netwm_def.h"
 
-#ifndef KWINDOWSYSTEM_NO_QWIDGET
-#include <QWidget>
-#endif
-
 #define KDE_ALL_ACTIVITIES_UUID "00000000-0000-0000-0000-000000000000"
 
 // forward declaration