diff --git a/tests/manual/windowflags/controllerwindow.cpp b/tests/manual/windowflags/controllerwindow.cpp
index b3657a3..2d012be 100644
--- a/tests/manual/windowflags/controllerwindow.cpp
+++ b/tests/manual/windowflags/controllerwindow.cpp
@@ -47,6 +47,9 @@
 #include <QGroupBox>
 #include <QApplication>
 #include <QHBoxLayout>
+#include <QWindowStateChangeEvent>
+#include <QWindow>
+#include <QDebug>
 
 #include "controllerwindow.h"
 #include "controls.h"
@@ -112,8 +115,19 @@ ControllerWindow::ControllerWindow() : previewWidget(0)
 
 bool ControllerWindow::eventFilter(QObject *o, QEvent *e)
 {
-    if (e->type() == QEvent::WindowStateChange)
-        updateStateControl();
+    if (e->type() == QEvent::WindowStateChange) {
+        QWindowStateChangeEvent *wse = static_cast<QWindowStateChangeEvent *>(e);
+        if (o->isWidgetType()) {
+            updateStateControl();
+            qDebug() << "widget" << wse->oldState() << static_cast<QWidget *>(o)->windowState();
+        } else if (o->isWindowType()) {
+            const Qt::WindowStates oldS = wse->oldState();
+            const Qt::WindowState newS = static_cast<QWindow*>(o)->windowState();
+            if (oldS == Qt::WindowMaximized && newS == Qt::WindowNoState)
+                qDebug() << "Max->Normal";
+            qDebug() << "window" << wse->oldState() << static_cast<QWindow*>(o)->windowState();
+        }
+    }
     return false;
 }
 
@@ -162,6 +176,13 @@ void ControllerWindow::updatePreview()
 
     previewWidget->setWindowState(statesControl->states());
     previewWidget->setVisible(statesControl->visibleValue());
+    static bool hasFilterOnWindow = false;
+    if (previewWidget->isVisible() && !hasFilterOnWindow) {
+        if (QWindow *w = previewWidget->windowHandle()) {
+            w->installEventFilter(this);
+            hasFilterOnWindow = true;
+        }
+    }
 }
 
 void ControllerWindow::createTypeGroupBox()
diff --git a/tests/manual/windowflags/windowflags.pro b/tests/manual/windowflags/windowflags.pro
index 546264c..97db359 100644
--- a/tests/manual/windowflags/windowflags.pro
+++ b/tests/manual/windowflags/windowflags.pro
@@ -9,3 +9,4 @@ SOURCES       = controllerwindow.cpp \
 
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
+CONFIG+=console