diff --git a/autotests/test_window_paint_data.cpp b/autotests/test_window_paint_data.cpp
--- a/autotests/test_window_paint_data.cpp
+++ b/autotests/test_window_paint_data.cpp
@@ -63,6 +63,7 @@
     virtual void enablePainting(int reason);
     virtual EffectWindow *findModal();
     virtual const EffectWindowGroup *group() const;
+    virtual bool isManaged() const;
     virtual bool isPaintingEnabled();
     virtual EffectWindowList mainWindows() const;
     virtual QByteArray readProperty(long int atom, long int type, int format) const;
@@ -121,6 +122,11 @@
     return nullptr;
 }
 
+bool MockEffectWindow::isManaged() const
+{
+    return true;
+}
+
 bool MockEffectWindow::isPaintingEnabled()
 {
     return true;
diff --git a/effects.h b/effects.h
--- a/effects.h
+++ b/effects.h
@@ -362,6 +362,8 @@
 
     const EffectWindowGroup* group() const override;
 
+    bool isManaged() const override;
+
     QRegion shape() const override;
     QRect decorationInnerRect() const override;
     QByteArray readProperty(long atom, long type, int format) const override;
@@ -406,6 +408,7 @@
     QHash<int, QVariant> dataMap;
     QHash<WindowThumbnailItem*, QWeakPointer<EffectWindowImpl> > m_thumbnails;
     QList<DesktopThumbnailItem*> m_desktopThumbnails;
+    bool m_managed;
 };
 
 class EffectWindowGroupImpl
diff --git a/effects.cpp b/effects.cpp
--- a/effects.cpp
+++ b/effects.cpp
@@ -1599,6 +1599,13 @@
     , toplevel(toplevel)
     , sw(NULL)
 {
+    // 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
+    // managed property of the toplevel during construction of EffectWindowImpl,
+    // so later on, when the toplevel has become Deleted, effects still
+    // can distinguish managed windows from unmanaged windows.
+    m_managed = toplevel->isClient();
 }
 
 EffectWindowImpl::~EffectWindowImpl()
@@ -1632,6 +1639,11 @@
     return NULL; // TODO
 }
 
+bool EffectWindowImpl::isManaged() const
+{
+    return m_managed;
+}
+
 void EffectWindowImpl::refWindow()
 {
     if (Deleted* d = dynamic_cast< Deleted* >(toplevel))
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -186,7 +186,7 @@
 
 #define KWIN_EFFECT_API_MAKE_VERSION( major, minor ) (( major ) << 8 | ( minor ))
 #define KWIN_EFFECT_API_VERSION_MAJOR 0
-#define KWIN_EFFECT_API_VERSION_MINOR 224
+#define KWIN_EFFECT_API_VERSION_MINOR 225
 #define KWIN_EFFECT_API_VERSION KWIN_EFFECT_API_MAKE_VERSION( \
         KWIN_EFFECT_API_VERSION_MAJOR, KWIN_EFFECT_API_VERSION_MINOR )
 
@@ -2135,7 +2135,7 @@
      * 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.
      */
diff --git a/libkwineffects/kwineffects.cpp b/libkwineffects/kwineffects.cpp
--- a/libkwineffects/kwineffects.cpp
+++ b/libkwineffects/kwineffects.cpp
@@ -810,7 +810,6 @@
 WINDOW_HELPER(bool, isOnScreenDisplay, "onScreenDisplay")
 WINDOW_HELPER(bool, isComboBox, "comboBox")
 WINDOW_HELPER(bool, isDNDIcon, "dndIcon")
-WINDOW_HELPER(bool, isManaged, "managed")
 WINDOW_HELPER(bool, isDeleted, "deleted")
 WINDOW_HELPER(bool, hasOwnShape, "shaped")
 WINDOW_HELPER(QString, windowRole, "windowRole")