diff --git a/autotests/test_window_paint_data.cpp b/autotests/test_window_paint_data.cpp
index 5ae193480d..24974f33d7 100644
--- a/autotests/test_window_paint_data.cpp
+++ b/autotests/test_window_paint_data.cpp
@@ -29,51 +29,217 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 using namespace KWin;
 
-class MockEffectWindowHelper : public QObject
-{
-    Q_OBJECT
-    Q_PROPERTY(qreal opacity READ opacity WRITE setOpacity)
-public:
-    MockEffectWindowHelper(QObject *parent = nullptr);
-    double opacity() const {
-        return m_opacity;
-    }
-    void setOpacity(qreal opacity) {
-        m_opacity = opacity;
-    }
-private:
-    qreal m_opacity;
-};
-
-MockEffectWindowHelper::MockEffectWindowHelper(QObject *parent)
-    : QObject(parent)
-    , m_opacity(1.0)
-{
-}
-
 class MockEffectWindow : public EffectWindow
 {
     Q_OBJECT
 public:
     MockEffectWindow(QObject *parent = nullptr);
-    virtual WindowQuadList buildQuads(bool force = false) const;
-    virtual QVariant data(int role) const;
-    virtual QRect decorationInnerRect() const;
-    virtual void deleteProperty(long int atom) const;
-    virtual void disablePainting(int reason);
-    virtual void enablePainting(int reason);
-    virtual EffectWindow *findModal();
-    virtual const EffectWindowGroup *group() const;
-    virtual bool isPaintingEnabled();
-    virtual EffectWindowList mainWindows() const;
-    virtual QByteArray readProperty(long int atom, long int type, int format) const;
-    virtual void refWindow();
-    virtual void unrefWindow();
-    virtual QRegion shape() const;
-    virtual void setData(int role, const QVariant &data);
-    virtual void referencePreviousWindowPixmap() {}
-    virtual void unreferencePreviousWindowPixmap() {}
-    QList<int> desktops() const { return {};}
+    WindowQuadList buildQuads(bool force = false) const override;
+    QVariant data(int role) const override;
+    QRect decorationInnerRect() const override;
+    void deleteProperty(long int atom) const override;
+    void disablePainting(int reason) override;
+    void enablePainting(int reason) override;
+    EffectWindow *findModal() override;
+    const EffectWindowGroup *group() const override;
+    bool isPaintingEnabled() override;
+    EffectWindowList mainWindows() const override;
+    QByteArray readProperty(long int atom, long int type, int format) const override;
+    void refWindow() override;
+    void unrefWindow() override;
+    QRegion shape() const override;
+    void setData(int role, const QVariant &data) override;
+    void referencePreviousWindowPixmap() override {}
+    void unreferencePreviousWindowPixmap() override {}
+    bool isDeleted() const override {
+        return false;
+    }
+    bool isMinimized() const override {
+        return false;
+    }
+    double opacity() const override {
+        return m_opacity;
+    }
+    void setOpacity(qreal opacity) {
+        m_opacity = opacity;
+    }
+    bool hasAlpha() const override {
+        return true;
+    }
+    QStringList activities() const override {
+        return QStringList();
+    }
+    int desktop() const override {
+        return 0;
+    }
+    QVector<uint> desktops() const override {
+        return {};
+    }
+    int x() const override {
+        return 0;
+    }
+    int y() const override {
+        return 0;
+    }
+    int width() const override {
+        return 100;
+    }
+    int height() const override {
+        return 100;
+    }
+    QSize basicUnit() const override {
+        return QSize();
+    }
+    QRect geometry() const override {
+        return QRect();
+    }
+    QRect expandedGeometry() const override {
+        return QRect();
+    }
+    int screen() const override {
+        return 0;
+    }
+    bool hasOwnShape() const override {
+        return false;
+    }
+    QPoint pos() const override {
+        return QPoint();
+    }
+    QSize size() const override {
+        return QSize(100,100);
+    }
+    QRect rect() const override {
+        return QRect(0,0,100,100);
+    }
+    bool isMovable() const override {
+        return true;
+    }
+    bool isMovableAcrossScreens() const override {
+        return true;
+    }
+    bool isUserMove() const override {
+        return false;
+    }
+    bool isUserResize() const override {
+        return false;
+    }
+    QRect iconGeometry() const override {
+        return QRect();
+    }
+    bool isDesktop() const override {
+        return false;
+    }
+    bool isDock() const override {
+        return false;
+    }
+    bool isToolbar() const override {
+        return false;
+    }
+    bool isMenu() const override {
+        return false;
+    }
+    bool isNormalWindow() const override {
+        return true;
+    }
+    bool isSpecialWindow() const override {
+        return false;
+    }
+    bool isDialog() const override {
+        return false;
+    }
+    bool isSplash() const override {
+        return false;
+    }
+    bool isUtility() const override {
+        return false;
+    }
+    bool isDropdownMenu() const override {
+        return false;
+    }
+    bool isPopupMenu() const override {
+        return false;
+    }
+    bool isTooltip() const override {
+        return false;
+    }
+    bool isNotification() const override {
+        return false;
+    }
+    bool isOnScreenDisplay() const override  {
+        return false;
+    }
+    bool isComboBox() const override {
+        return false;
+    }
+    bool isDNDIcon() const override {
+        return false;
+    }
+    QRect contentsRect() const override {
+        return QRect();
+    }
+    bool decorationHasAlpha() const override {
+        return false;
+    }
+    QString caption() const override {
+        return QString();
+    }
+    QIcon icon() const override {
+        return QIcon();
+    }
+    QString windowClass() const override {
+        return QString();
+    }
+    QString windowRole() const override {
+        return QString();
+    }
+    NET::WindowType windowType() const override {
+        return NET::Normal;
+    }
+    bool acceptsFocus() const override {
+        return true;
+    }
+    bool keepAbove() const override {
+        return false;
+    }
+    bool keepBelow() const override {
+        return false;
+    }
+    bool isModal() const override {
+        return false;
+    }
+    bool isSkipSwitcher() const override {
+        return false;
+    }
+    bool isCurrentTab() const override {
+        return true;
+    }
+    bool skipsCloseAnimation() const override {
+        return false;
+    }
+    KWayland::Server::SurfaceInterface *surface() const override {
+        return nullptr;
+    }
+    bool isFullScreen() const override {
+        return false;
+    }
+    bool isUnresponsive() const override {
+        return false;
+    }
+    bool isPopupWindow() const override {
+        return false;
+    }
+    bool isManaged() const override {
+        return true;
+    }
+    bool isWaylandClient() const override {
+        return true;
+    }
+    bool isX11Client() const override {
+        return false;
+    }
+
+private:
+    qreal m_opacity = 1.0;
 };
 
 MockEffectWindow::MockEffectWindow(QObject *parent)
@@ -175,9 +341,8 @@ private Q_SLOTS:
 
 void TestWindowPaintData::testCtor()
 {
-    MockEffectWindowHelper helper;
-    helper.setOpacity(0.5);
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
+    w.setOpacity(0.5);
     WindowPaintData data(&w);
     QCOMPARE(data.xScale(), 1.0);
     QCOMPARE(data.yScale(), 1.0);
@@ -196,8 +361,7 @@ void TestWindowPaintData::testCtor()
 
 void TestWindowPaintData::testCopyCtor()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     WindowPaintData data2(data);
     // no value had been changed
@@ -242,8 +406,7 @@ void TestWindowPaintData::testCopyCtor()
 
 void TestWindowPaintData::testOperatorMultiplyAssign()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     // without anything set, it's 1.0 on all axis
     QCOMPARE(data.xScale(), 1.0);
@@ -268,8 +431,7 @@ void TestWindowPaintData::testOperatorMultiplyAssign()
 
 void TestWindowPaintData::testOperatorPlus()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     QCOMPARE(data.xTranslation(), 0.0);
     QCOMPARE(data.yTranslation(), 0.0);
@@ -291,8 +453,7 @@ void TestWindowPaintData::testOperatorPlus()
 
 void TestWindowPaintData::testMultiplyBrightness()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     QCOMPARE(0.2, data.multiplyBrightness(0.2));
     QCOMPARE(0.2, data.brightness());
@@ -305,8 +466,7 @@ void TestWindowPaintData::testMultiplyBrightness()
 
 void TestWindowPaintData::testMultiplyOpacity()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     QCOMPARE(0.2, data.multiplyOpacity(0.2));
     QCOMPARE(0.2, data.opacity());
@@ -319,8 +479,7 @@ void TestWindowPaintData::testMultiplyOpacity()
 
 void TestWindowPaintData::testMultiplySaturation()
 {
-    MockEffectWindowHelper helper;
-    MockEffectWindow w(&helper);
+    MockEffectWindow w;
     WindowPaintData data(&w);
     QCOMPARE(0.2, data.multiplySaturation(0.2));
     QCOMPARE(0.2, data.saturation());
diff --git a/deleted.cpp b/deleted.cpp
index 06f727db49..1fc12dc979 100644
--- a/deleted.cpp
+++ b/deleted.cpp
@@ -254,6 +254,20 @@ QByteArray Deleted::windowRole() const
     return m_windowRole;
 }
 
+QVector<uint> Deleted::x11DesktopIds() const
+{
+    const auto desks = desktops();
+    QVector<uint> x11Ids;
+    x11Ids.reserve(desks.count());
+    std::transform(desks.constBegin(), desks.constEnd(),
+        std::back_inserter(x11Ids),
+        [] (const VirtualDesktop *vd) {
+            return vd->x11DesktopNumber();
+        }
+    );
+    return x11Ids;
+}
+
 void Deleted::addTransient(Deleted *transient)
 {
     m_transients.append(transient);
diff --git a/deleted.h b/deleted.h
index a2dd663fe7..132b61abf4 100644
--- a/deleted.h
+++ b/deleted.h
@@ -181,6 +181,8 @@ public:
         return m_wasPopupWindow;
     }
 
+    QVector<uint> x11DesktopIds() const;
+
 protected:
     virtual void debug(QDebug& stream) const;
 private Q_SLOTS:
diff --git a/effects.cpp b/effects.cpp
index 13da4f31a8..61f96e8c54 100644
--- a/effects.cpp
+++ b/effects.cpp
@@ -1658,8 +1658,19 @@ KSharedConfigPtr EffectsHandlerImpl::inputConfig() const
 EffectWindowImpl::EffectWindowImpl(Toplevel *toplevel)
     : EffectWindow(toplevel)
     , toplevel(toplevel)
-    , sw(NULL)
+    , sw(nullptr)
 {
+    // Deleted windows are not managed. So, when windowClosed signal is
+    // emitted, effects can't distinguish managed windows from unmanaged
+    // windows(e.g. combo box popups, popup menus, etc). Save value of the
+    // managed property during construction of EffectWindow. At that time,
+    // parent can be Client, ShellClient, or Unmanaged. So, later on, when
+    // an instance of Deleted becomes parent of the EffectWindow, effects
+    // can still figure out whether it is/was a managed window.
+    managed = toplevel->isClient();
+
+    waylandClient = qobject_cast<KWin::ShellClient *>(toplevel) != nullptr;
+    x11Client = !waylandClient;
 }
 
 EffectWindowImpl::~EffectWindowImpl()
@@ -1690,7 +1701,7 @@ const EffectWindowGroup* EffectWindowImpl::group() const
 {
     if (Client* c = dynamic_cast< Client* >(toplevel))
         return c->group()->effectGroup();
-    return NULL; // TODO
+    return nullptr; // TODO
 }
 
 void EffectWindowImpl::refWindow()
@@ -1707,6 +1718,122 @@ void EffectWindowImpl::unrefWindow()
     abort(); // TODO
 }
 
+#define TOPLEVEL_HELPER( rettype, prototype, toplevelPrototype) \
+    rettype EffectWindowImpl::prototype ( ) const \
+    { \
+        return toplevel->toplevelPrototype(); \
+    }
+
+TOPLEVEL_HELPER(double, opacity, opacity)
+TOPLEVEL_HELPER(bool, hasAlpha, hasAlpha)
+TOPLEVEL_HELPER(int, x, x)
+TOPLEVEL_HELPER(int, y, y)
+TOPLEVEL_HELPER(int, width, width)
+TOPLEVEL_HELPER(int, height, height)
+TOPLEVEL_HELPER(QPoint, pos, pos)
+TOPLEVEL_HELPER(QSize, size, size)
+TOPLEVEL_HELPER(int, screen, screen)
+TOPLEVEL_HELPER(QRect, geometry, geometry)
+TOPLEVEL_HELPER(QRect, expandedGeometry, visibleRect)
+TOPLEVEL_HELPER(QRect, rect, rect)
+TOPLEVEL_HELPER(int, desktop, desktop)
+TOPLEVEL_HELPER(bool, isDesktop, isDesktop)
+TOPLEVEL_HELPER(bool, isDock, isDock)
+TOPLEVEL_HELPER(bool, isToolbar, isToolbar)
+TOPLEVEL_HELPER(bool, isMenu, isMenu)
+TOPLEVEL_HELPER(bool, isNormalWindow, isNormalWindow)
+TOPLEVEL_HELPER(bool, isDialog, isDialog)
+TOPLEVEL_HELPER(bool, isSplash, isSplash)
+TOPLEVEL_HELPER(bool, isUtility, isUtility)
+TOPLEVEL_HELPER(bool, isDropdownMenu, isDropdownMenu)
+TOPLEVEL_HELPER(bool, isPopupMenu, isPopupMenu)
+TOPLEVEL_HELPER(bool, isTooltip, isTooltip)
+TOPLEVEL_HELPER(bool, isNotification, isNotification)
+TOPLEVEL_HELPER(bool, isOnScreenDisplay, isOnScreenDisplay)
+TOPLEVEL_HELPER(bool, isComboBox, isComboBox)
+TOPLEVEL_HELPER(bool, isDNDIcon, isDNDIcon)
+TOPLEVEL_HELPER(bool, isDeleted, isDeleted)
+TOPLEVEL_HELPER(bool, hasOwnShape, shape)
+TOPLEVEL_HELPER(QString, windowRole, windowRole)
+TOPLEVEL_HELPER(QStringList, activities, activities)
+TOPLEVEL_HELPER(bool, skipsCloseAnimation, skipsCloseAnimation)
+TOPLEVEL_HELPER(KWayland::Server::SurfaceInterface *, surface, surface)
+TOPLEVEL_HELPER(bool, isPopupWindow, isPopupWindow)
+
+#undef TOPLEVEL_HELPER
+
+#define CLIENT_HELPER_WITH_DELETED( rettype, prototype, propertyname, defaultValue ) \
+    rettype EffectWindowImpl::prototype ( ) const \
+    { \
+        auto client = qobject_cast<AbstractClient *>(toplevel); \
+        if (client) { \
+            return client->propertyname(); \
+        } \
+        auto deleted = qobject_cast<Deleted *>(toplevel); \
+        if (deleted) { \
+            return deleted->propertyname(); \
+        } \
+        return defaultValue; \
+    }
+
+CLIENT_HELPER_WITH_DELETED(bool, isMinimized, isMinimized, false)
+CLIENT_HELPER_WITH_DELETED(bool, isModal, isModal, false)
+CLIENT_HELPER_WITH_DELETED(bool, isFullScreen, isFullScreen, false)
+CLIENT_HELPER_WITH_DELETED(bool, isCurrentTab, isCurrentTab, false)
+CLIENT_HELPER_WITH_DELETED(bool, keepAbove, keepAbove, false)
+CLIENT_HELPER_WITH_DELETED(bool, keepBelow, keepBelow, false)
+CLIENT_HELPER_WITH_DELETED(QString, caption, caption, QString());
+CLIENT_HELPER_WITH_DELETED(QVector<uint>, desktops, x11DesktopIds, QVector<uint>());
+
+#undef CLIENT_HELPER_WITH_DELETED
+
+QString EffectWindowImpl::windowClass() const
+{
+    return toplevel->resourceName() + QLatin1Char(' ') + toplevel->resourceClass();
+}
+
+QRect EffectWindowImpl::contentsRect() const
+{
+    return QRect(toplevel->clientPos(), toplevel->clientSize());
+}
+
+NET::WindowType EffectWindowImpl::windowType() const
+{
+    return toplevel->windowType();
+}
+
+#define CLIENT_HELPER( rettype, prototype, propertyname, defaultValue ) \
+    rettype EffectWindowImpl::prototype ( ) const \
+    { \
+        auto client = qobject_cast<AbstractClient *>(toplevel); \
+        if (client) { \
+            return client->propertyname(); \
+        } \
+        return defaultValue; \
+    }
+
+CLIENT_HELPER(bool, isMovable, isMovable, false)
+CLIENT_HELPER(bool, isMovableAcrossScreens, isMovableAcrossScreens, false)
+CLIENT_HELPER(bool, isUserMove, isMove, false)
+CLIENT_HELPER(bool, isUserResize, isResize, false)
+CLIENT_HELPER(QRect, iconGeometry, iconGeometry, QRect())
+CLIENT_HELPER(bool, isSpecialWindow, isSpecialWindow, true)
+CLIENT_HELPER(bool, acceptsFocus, wantsInput, true) // We don't actually know...
+CLIENT_HELPER(QIcon, icon, icon, QIcon())
+CLIENT_HELPER(bool, isSkipSwitcher, skipSwitcher, false)
+CLIENT_HELPER(bool, decorationHasAlpha, decorationHasAlpha, false)
+CLIENT_HELPER(bool, isUnresponsive, unresponsive, false)
+
+#undef CLIENT_HELPER
+
+QSize EffectWindowImpl::basicUnit() const
+{
+    if (auto client = qobject_cast<Client*>(toplevel)){
+        return client->basicUnit();
+    }
+    return QSize(1,1);
+}
+
 void EffectWindowImpl::setWindow(Toplevel* w)
 {
     toplevel = w;
@@ -1868,6 +1995,22 @@ void EffectWindowImpl::unreferencePreviousWindowPixmap()
     }
 }
 
+bool EffectWindowImpl::isManaged() const
+{
+    return managed;
+}
+
+bool EffectWindowImpl::isWaylandClient() const
+{
+    return waylandClient;
+}
+
+bool EffectWindowImpl::isX11Client() const
+{
+    return x11Client;
+}
+
+
 //****************************************
 // EffectWindowGroupImpl
 //****************************************
diff --git a/effects.h b/effects.h
index 16ff2662b7..e7edf04553 100644
--- a/effects.h
+++ b/effects.h
@@ -357,7 +357,7 @@ class EffectWindowImpl : public EffectWindow
     Q_OBJECT
 public:
     explicit EffectWindowImpl(Toplevel *toplevel);
-    virtual ~EffectWindowImpl();
+    ~EffectWindowImpl() override;
 
     void enablePainting(int reason) override;
     void disablePainting(int reason) override;
@@ -368,7 +368,79 @@ public:
 
     const EffectWindowGroup* group() const override;
 
+    bool isDeleted() const override;
+    bool isMinimized() const override;
+    double opacity() const override;
+    bool hasAlpha() const override;
+
+    QStringList activities() const override;
+    int desktop() const override;
+    QVector<uint> desktops() const override;
+    int x() const override;
+    int y() const override;
+    int width() const override;
+    int height() const override;
+
+    QSize basicUnit() const override;
+    QRect geometry() const override;
+
+    QString caption() const override;
+
+    QRect expandedGeometry() const override;
     QRegion shape() const override;
+    int screen() const override;
+    bool hasOwnShape() const override; // only for shadow effect, for now
+    QPoint pos() const override;
+    QSize size() const override;
+    QRect rect() const override;
+
+    bool isMovable() const override;
+    bool isMovableAcrossScreens() const override;
+    bool isUserMove() const override;
+    bool isUserResize() const override;
+    QRect iconGeometry() const override;
+
+    bool isDesktop() const override;
+    bool isDock() const override;
+    bool isToolbar() const override;
+    bool isMenu() const override;
+    bool isNormalWindow() const override;
+    bool isSpecialWindow() const override;
+    bool isDialog() const override;
+    bool isSplash() const override;
+    bool isUtility() const override;
+    bool isDropdownMenu() const override;
+    bool isPopupMenu() const override;
+    bool isTooltip() const override;
+    bool isNotification() const override;
+    bool isOnScreenDisplay() const override;
+    bool isComboBox() const override;
+    bool isDNDIcon() const override;
+    bool skipsCloseAnimation() const override;
+
+    bool acceptsFocus() const override;
+    bool keepAbove() const override;
+    bool keepBelow() const override;
+    bool isModal() const override;
+    bool isPopupWindow() const override;
+
+    KWayland::Server::SurfaceInterface *surface() const override;
+    bool isFullScreen() const override;
+    bool isUnresponsive() const override;
+
+    QRect contentsRect() const override;
+    bool decorationHasAlpha() const override;
+    QIcon icon() const override;
+    QString windowClass() const override;
+    NET::WindowType windowType() const override;
+    bool isSkipSwitcher() const override;
+    bool isCurrentTab() const override;
+    QString windowRole() const override;
+
+    bool isManaged() const override;
+    bool isWaylandClient() const override;
+    bool isX11Client() const override;
+
     QRect decorationInnerRect() const override;
     QByteArray readProperty(long atom, long type, int format) const override;
     void deleteProperty(long atom) const override;
@@ -401,6 +473,7 @@ public:
     QList<DesktopThumbnailItem*> const &desktopThumbnails() const {
         return m_desktopThumbnails;
     }
+
 private Q_SLOTS:
     void thumbnailDestroyed(QObject *object);
     void thumbnailTargetChanged();
@@ -412,6 +485,9 @@ private:
     QHash<int, QVariant> dataMap;
     QHash<WindowThumbnailItem*, QWeakPointer<EffectWindowImpl> > m_thumbnails;
     QList<DesktopThumbnailItem*> m_desktopThumbnails;
+    bool managed = false;
+    bool waylandClient;
+    bool x11Client;
 };
 
 class EffectWindowGroupImpl
diff --git a/libkwineffects/kwineffects.cpp b/libkwineffects/kwineffects.cpp
index 5ddce914e4..8b5345bffa 100644
--- a/libkwineffects/kwineffects.cpp
+++ b/libkwineffects/kwineffects.cpp
@@ -775,9 +775,6 @@ public:
     Private(EffectWindow *q);
 
     EffectWindow *q;
-    bool managed = false;
-    bool waylandClient;
-    bool x11Client;
 };
 
 EffectWindow::Private::Private(EffectWindow *q)
@@ -789,128 +786,23 @@ EffectWindow::EffectWindow(QObject *parent)
     : QObject(parent)
     , d(new Private(this))
 {
-    // Deleted windows are not managed. So, when windowClosed signal is
-    // emitted, effects can't distinguish managed windows from unmanaged
-    // windows(e.g. combo box popups, popup menus, etc). Save value of the
-    // managed property during construction of EffectWindow. At that time,
-    // parent can be Client, ShellClient, or Unmanaged. So, later on, when
-    // an instance of Deleted becomes parent of the EffectWindow, effects
-    // can still figure out whether it is/was a managed window.
-    d->managed = parent->property("managed").value<bool>();
-
-    d->waylandClient = parent->inherits("KWin::ShellClient");
-    d->x11Client = !d->waylandClient;
 }
 
 EffectWindow::~EffectWindow()
 {
 }
 
-#define WINDOW_HELPER( rettype, prototype, propertyname ) \
-    rettype EffectWindow::prototype ( ) const \
-    { \
-        return parent()->property( propertyname ).value< rettype >(); \
-    }
-
-WINDOW_HELPER(double, opacity, "opacity")
-WINDOW_HELPER(bool, hasAlpha, "alpha")
-WINDOW_HELPER(int, x, "x")
-WINDOW_HELPER(int, y, "y")
-WINDOW_HELPER(int, width, "width")
-WINDOW_HELPER(int, height, "height")
-WINDOW_HELPER(QPoint, pos, "pos")
-WINDOW_HELPER(QSize, size, "size")
-WINDOW_HELPER(int, screen, "screen")
-WINDOW_HELPER(QRect, geometry, "geometry")
-WINDOW_HELPER(QRect, expandedGeometry, "visibleRect")
-WINDOW_HELPER(QRect, rect, "rect")
-#ifndef KWIN_NO_DEPRECATED
-WINDOW_HELPER(int, desktop, "desktop")
-#endif
-WINDOW_HELPER(bool, isDesktop, "desktopWindow")
-WINDOW_HELPER(bool, isDock, "dock")
-WINDOW_HELPER(bool, isToolbar, "toolbar")
-WINDOW_HELPER(bool, isMenu, "menu")
-WINDOW_HELPER(bool, isNormalWindow, "normalWindow")
-WINDOW_HELPER(bool, isDialog, "dialog")
-WINDOW_HELPER(bool, isSplash, "splash")
-WINDOW_HELPER(bool, isUtility, "utility")
-WINDOW_HELPER(bool, isDropdownMenu, "dropdownMenu")
-WINDOW_HELPER(bool, isPopupMenu, "popupMenu")
-WINDOW_HELPER(bool, isTooltip, "tooltip")
-WINDOW_HELPER(bool, isNotification, "notification")
-WINDOW_HELPER(bool, isOnScreenDisplay, "onScreenDisplay")
-WINDOW_HELPER(bool, isComboBox, "comboBox")
-WINDOW_HELPER(bool, isDNDIcon, "dndIcon")
-WINDOW_HELPER(bool, isDeleted, "deleted")
-WINDOW_HELPER(bool, hasOwnShape, "shaped")
-WINDOW_HELPER(QString, windowRole, "windowRole")
-WINDOW_HELPER(QStringList, activities, "activities")
-WINDOW_HELPER(bool, skipsCloseAnimation, "skipsCloseAnimation")
-WINDOW_HELPER(KWayland::Server::SurfaceInterface *, surface, "surface")
-WINDOW_HELPER(QVector<uint>, desktops, "x11DesktopIds")
-WINDOW_HELPER(bool, isPopupWindow, "popupWindow")
-
-QString EffectWindow::windowClass() const
-{
-    return parent()->property("resourceName").toString() + QLatin1Char(' ') + parent()->property("resourceClass").toString();
-}
-
-QRect EffectWindow::contentsRect() const
-{
-    return QRect(parent()->property("clientPos").toPoint(), parent()->property("clientSize").toSize());
-}
-
-NET::WindowType EffectWindow::windowType() const
-{
-    return static_cast<NET::WindowType>(parent()->property("windowType").toInt());
-}
-
 bool EffectWindow::isOnActivity(QString activity) const
 {
-    const QStringList activities = parent()->property("activities").toStringList();
-    return activities.isEmpty() || activities.contains(activity);
+    const QStringList _activities = activities();
+    return _activities.isEmpty() || _activities.contains(activity);
 }
 
 bool EffectWindow::isOnAllActivities() const
 {
-    return parent()->property("activities").toStringList().isEmpty();
+    return activities().isEmpty();
 }
 
-#undef WINDOW_HELPER
-
-#define WINDOW_HELPER_DEFAULT( rettype, prototype, propertyname, defaultValue ) \
-    rettype EffectWindow::prototype ( ) const \
-    { \
-        const QVariant variant = parent()->property( propertyname ); \
-        if (!variant.isValid()) { \
-            return defaultValue; \
-        } \
-        return variant.value< rettype >(); \
-    }
-
-WINDOW_HELPER_DEFAULT(bool, isMinimized, "minimized", false)
-WINDOW_HELPER_DEFAULT(bool, isMovable, "moveable", false)
-WINDOW_HELPER_DEFAULT(bool, isMovableAcrossScreens, "moveableAcrossScreens", false)
-WINDOW_HELPER_DEFAULT(QString, caption, "caption", QString())
-WINDOW_HELPER_DEFAULT(bool, keepAbove, "keepAbove", true)
-WINDOW_HELPER_DEFAULT(bool, keepBelow, "keepBelow", false)
-WINDOW_HELPER_DEFAULT(bool, isModal, "modal", false)
-WINDOW_HELPER_DEFAULT(QSize, basicUnit, "basicUnit", QSize(1, 1))
-WINDOW_HELPER_DEFAULT(bool, isUserMove, "move", false)
-WINDOW_HELPER_DEFAULT(bool, isUserResize, "resize", false)
-WINDOW_HELPER_DEFAULT(QRect, iconGeometry, "iconGeometry", QRect())
-WINDOW_HELPER_DEFAULT(bool, isSpecialWindow, "specialWindow", true)
-WINDOW_HELPER_DEFAULT(bool, acceptsFocus, "wantsInput", true) // We don't actually know...
-WINDOW_HELPER_DEFAULT(QIcon, icon, "icon", QIcon())
-WINDOW_HELPER_DEFAULT(bool, isSkipSwitcher, "skipSwitcher", false)
-WINDOW_HELPER_DEFAULT(bool, isCurrentTab, "isCurrentTab", true)
-WINDOW_HELPER_DEFAULT(bool, decorationHasAlpha, "decorationHasAlpha", false)
-WINDOW_HELPER_DEFAULT(bool, isFullScreen, "fullScreen", false)
-WINDOW_HELPER_DEFAULT(bool, isUnresponsive, "unresponsive", false)
-
-#undef WINDOW_HELPER_DEFAULT
-
 #define WINDOW_HELPER_SETTER( prototype, propertyname, args, value ) \
     void EffectWindow::prototype ( args ) \
     {\
@@ -997,21 +889,6 @@ bool EffectWindow::isVisible() const
            && isOnCurrentActivity();
 }
 
-bool EffectWindow::isManaged() const
-{
-    return d->managed;
-}
-
-bool EffectWindow::isWaylandClient() const
-{
-    return d->waylandClient;
-}
-
-bool EffectWindow::isX11Client() const
-{
-    return d->x11Client;
-}
-
 //****************************************
 // EffectWindowGroup
 //****************************************
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
index e2f121e931..ae9b658c47 100644
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -2071,16 +2071,17 @@ public:
 
     virtual void refWindow() = 0;
     virtual void unrefWindow() = 0;
-    bool isDeleted() const;
 
-    bool isMinimized() const;
-    double opacity() const;
-    bool hasAlpha() const;
+    virtual bool isDeleted() const = 0;
+
+    virtual bool isMinimized() const = 0;
+    virtual double opacity() const = 0;
+    virtual bool hasAlpha() const = 0;
 
     bool isOnCurrentActivity() const;
     Q_SCRIPTABLE bool isOnActivity(QString id) const;
     bool isOnAllActivities() const;
-    QStringList activities() const;
+    virtual QStringList activities() const = 0;
 
     Q_SCRIPTABLE bool isOnDesktop(int d) const;
     bool isOnCurrentDesktop() const;
@@ -2094,48 +2095,48 @@ public:
      * @deprecated
      */
 #ifndef KWIN_NO_DEPRECATED
-    int KWIN_DEPRECATED desktop() const; // prefer isOnXXX()
+    virtual int KWIN_DEPRECATED desktop() const = 0; // prefer isOnXXX()
 #endif
     /**
      * All the desktops by number that the window is in. On X11 this list will always have
      * a length of 1, on Wayland can be any subset.
      * If the list is empty it means the window is on all desktops
      */
-    QVector<uint> desktops() const;
+    virtual QVector<uint> desktops() const = 0;
 
-    int x() const;
-    int y() const;
-    int width() const;
-    int height() const;
+    virtual int x() const = 0;
+    virtual int y() const = 0;
+    virtual int width() const = 0;
+    virtual int height() const = 0;
     /**
      * By how much the window wishes to grow/shrink at least. Usually QSize(1,1).
      * MAY BE DISOBEYED BY THE WM! It's only for information, do NOT rely on it at all.
      */
-    QSize basicUnit() const;
-    QRect geometry() const;
+    virtual QSize basicUnit() const = 0;
+    virtual QRect geometry() const = 0;
     /**
      * Geometry of the window including decoration and potentially shadows.
      * May be different from geometry() if the window has a shadow.
      * @since 4.9
      */
-    QRect expandedGeometry() const;
+    virtual QRect expandedGeometry() const = 0;
     virtual QRegion shape() const = 0;
-    int screen() const;
+    virtual int screen() const = 0;
     /** @internal Do not use */
-    bool hasOwnShape() const; // only for shadow effect, for now
-    QPoint pos() const;
-    QSize size() const;
-    QRect rect() const;
-    bool isMovable() const;
-    bool isMovableAcrossScreens() const;
-    bool isUserMove() const;
-    bool isUserResize() const;
-    QRect iconGeometry() const;
+    virtual bool hasOwnShape() const = 0; // only for shadow effect, for now
+    virtual QPoint pos() const = 0;
+    virtual QSize size() const = 0;
+    virtual QRect rect() const = 0;
+    virtual bool isMovable() const = 0;
+    virtual bool isMovableAcrossScreens() const = 0;
+    virtual bool isUserMove() const = 0;
+    virtual bool isUserResize() const = 0;
+    virtual QRect iconGeometry() const = 0;
 
     /**
      * Geometry of the actual window contents inside the whole (including decorations) window.
      */
-    QRect contentsRect() const;
+    virtual QRect contentsRect() const = 0;
     /**
      * Geometry of the transparent rect in the decoration.
      * May be different from contentsRect() if the decoration is extended into the client area.
@@ -2143,124 +2144,124 @@ public:
      */
     virtual QRect decorationInnerRect() const = 0;
     bool hasDecoration() const;
-    bool decorationHasAlpha() const;
+    virtual bool decorationHasAlpha() const = 0;
     virtual QByteArray readProperty(long atom, long type, int format) const = 0;
     virtual void deleteProperty(long atom) const = 0;
 
-    QString caption() const;
-    QIcon icon() const;
-    QString windowClass() const;
-    QString windowRole() const;
+    virtual QString caption() const = 0;
+    virtual QIcon icon() const = 0;
+    virtual QString windowClass() const = 0;
+    virtual QString windowRole() const = 0;
     virtual const EffectWindowGroup* group() const = 0;
 
     /**
      * Returns whether the window is a desktop background window (the one with wallpaper).
      * See _NET_WM_WINDOW_TYPE_DESKTOP at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isDesktop() const;
+    virtual bool isDesktop() const = 0;
     /**
      * Returns whether the window is a dock (i.e. a panel).
      * See _NET_WM_WINDOW_TYPE_DOCK at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isDock() const;
+    virtual bool isDock() const = 0;
     /**
      * Returns whether the window is a standalone (detached) toolbar window.
      * See _NET_WM_WINDOW_TYPE_TOOLBAR at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isToolbar() const;
+    virtual bool isToolbar() const = 0;
     /**
      * Returns whether the window is a torn-off menu.
      * See _NET_WM_WINDOW_TYPE_MENU at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isMenu() const;
+    virtual bool isMenu() const = 0;
     /**
      * Returns whether the window is a "normal" window, i.e. an application or any other window
      * for which none of the specialized window types fit.
      * See _NET_WM_WINDOW_TYPE_NORMAL at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isNormalWindow() const; // normal as in 'NET::Normal or NET::Unknown non-transient'
+    virtual bool isNormalWindow() const = 0; // normal as in 'NET::Normal or NET::Unknown non-transient'
     /**
      * Returns whether the window is any of special windows types (desktop, dock, splash, ...),
      * i.e. window types that usually don't have a window frame and the user does not use window
      * management (moving, raising,...) on them.
      */
-    bool isSpecialWindow() const;
+    virtual bool isSpecialWindow() const = 0;
     /**
      * Returns whether the window is a dialog window.
      * See _NET_WM_WINDOW_TYPE_DIALOG at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isDialog() const;
+    virtual bool isDialog() const = 0;
     /**
      * Returns whether the window is a splashscreen. Note that many (especially older) applications
      * do not support marking their splash windows with this type.
      * See _NET_WM_WINDOW_TYPE_SPLASH at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isSplash() const;
+    virtual bool isSplash() const = 0;
     /**
      * Returns whether the window is a utility window, such as a tool window.
      * See _NET_WM_WINDOW_TYPE_UTILITY at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isUtility() const;
+    virtual bool isUtility() const = 0;
     /**
      * Returns whether the window is a dropdown menu (i.e. a popup directly or indirectly open
      * from the applications menubar).
      * See _NET_WM_WINDOW_TYPE_DROPDOWN_MENU at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isDropdownMenu() const;
+    virtual bool isDropdownMenu() const = 0;
     /**
      * Returns whether the window is a popup menu (that is not a torn-off or dropdown menu).
      * See _NET_WM_WINDOW_TYPE_POPUP_MENU at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isPopupMenu() const; // a context popup, not dropdown, not torn-off
+    virtual bool isPopupMenu() const = 0; // a context popup, not dropdown, not torn-off
     /**
      * Returns whether the window is a tooltip.
      * See _NET_WM_WINDOW_TYPE_TOOLTIP at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isTooltip() const;
+    virtual bool isTooltip() const = 0;
     /**
      * Returns whether the window is a window with a notification.
      * See _NET_WM_WINDOW_TYPE_NOTIFICATION at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isNotification() const;
+    virtual bool isNotification() const = 0;
     /**
      * Returns whether the window is an on screen display window
      * using the non-standard _KDE_NET_WM_WINDOW_TYPE_ON_SCREEN_DISPLAY
      */
-    bool isOnScreenDisplay() const;
+    virtual bool isOnScreenDisplay() const = 0;
     /**
      * Returns whether the window is a combobox popup.
      * See _NET_WM_WINDOW_TYPE_COMBO at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isComboBox() const;
+    virtual bool isComboBox() const = 0;
     /**
      * Returns whether the window is a Drag&Drop icon.
      * See _NET_WM_WINDOW_TYPE_DND at http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    bool isDNDIcon() const;
+    virtual bool isDNDIcon() const = 0;
     /**
      * Returns the NETWM window type
      * See http://standards.freedesktop.org/wm-spec/wm-spec-latest.html .
      */
-    NET::WindowType windowType() const;
+    virtual NET::WindowType windowType() const = 0;
     /**
      * Returns whether the window is managed by KWin (it has control over its placement and other
      * aspects, as opposed to override-redirect windows that are entirely handled by the application).
      */
-    bool isManaged() const; // whether it's managed or override-redirect
+    virtual bool isManaged() const = 0; // whether it's managed or override-redirect
     /**
      * Returns whether or not the window can accept keyboard focus.
      */
-    bool acceptsFocus() const;
+    virtual bool acceptsFocus() const = 0;
     /**
      * Returns whether or not the window is kept above all other windows.
      */
-    bool keepAbove() const;
+    virtual bool keepAbove() const = 0;
     /**
      * Returns whether the window is kept below all other windows.
      */
-    bool keepBelow() const;
+    virtual bool keepBelow() const = 0;
 
-    bool isModal() const;
+    virtual bool isModal() const = 0;
     Q_SCRIPTABLE virtual KWin::EffectWindow* findModal() = 0;
     Q_SCRIPTABLE virtual QList<KWin::EffectWindow*> mainWindows() const = 0;
 
@@ -2268,7 +2269,7 @@ public:
     * Returns whether the window should be excluded from window switching effects.
     * @since 4.5
     */
-    bool isSkipSwitcher() const;
+    virtual bool isSkipSwitcher() const = 0;
 
     /**
      * Returns the unmodified window quad list. Can also be used to force rebuilding.
@@ -2280,7 +2281,7 @@ public:
     void unminimize();
     Q_SCRIPTABLE void closeWindow() const;
 
-    bool isCurrentTab() const;
+    virtual bool isCurrentTab() const = 0;
 
     /**
      * @since 4.11
@@ -2290,37 +2291,37 @@ public:
     /**
      * @since 5.0
      **/
-    bool skipsCloseAnimation() const;
+    virtual bool skipsCloseAnimation() const = 0;
 
     /**
      * @since 5.5
      */
-    KWayland::Server::SurfaceInterface *surface() const;
+    virtual KWayland::Server::SurfaceInterface *surface() const = 0;
 
     /**
      * @since 5.6
      **/
-    bool isFullScreen() const;
+    virtual bool isFullScreen() const = 0;
 
     /**
      * @since 5.10
      */
-    bool isUnresponsive() const;
+    virtual bool isUnresponsive() const = 0;
 
     /**
      * @since 5.15
      **/
-    bool isWaylandClient() const;
+    virtual bool isWaylandClient() const = 0;
 
     /**
      * @since 5.15
      **/
-    bool isX11Client() const;
+    virtual bool isX11Client() const = 0;
 
     /**
      * @since 5.15
      **/
-    bool isPopupWindow() const;
+    virtual bool isPopupWindow() const = 0;
 
     /**
      * Can be used to by effects to store arbitrary data in the EffectWindow.