diff --git a/scene.h b/scene.h
--- a/scene.h
+++ b/scene.h
@@ -538,12 +538,6 @@
 }
 
 inline
-void Scene::Window::updateShadow(Shadow* shadow)
-{
-    m_shadow = shadow;
-}
-
-inline
 const Shadow* Scene::Window::shadow() const
 {
     return m_shadow;
diff --git a/scene.cpp b/scene.cpp
--- a/scene.cpp
+++ b/scene.cpp
@@ -928,6 +928,15 @@
     return ret;
 }
 
+void Scene::Window::updateShadow(Shadow* shadow)
+{
+    if (m_shadow == shadow) {
+        return;
+    }
+    delete m_shadow;
+    m_shadow = shadow;
+}
+
 //****************************************
 // WindowPixmap
 //****************************************
diff --git a/shadow.cpp b/shadow.cpp
--- a/shadow.cpp
+++ b/shadow.cpp
@@ -337,10 +337,11 @@
     auto clear = [this]() {
         if (m_topLevel && m_topLevel->effectWindow() && m_topLevel->effectWindow()->sceneWindow() &&
                                             m_topLevel->effectWindow()->sceneWindow()->shadow()) {
-            m_topLevel->effectWindow()->sceneWindow()->updateShadow(0);
-            m_topLevel->effectWindow()->buildQuads(true);
+            auto w = m_topLevel->effectWindow();
+            // this also deletes the shadow
+            w->sceneWindow()->updateShadow(nullptr);
+            w->buildQuads(true);
         }
-        deleteLater();
     };
     if (m_decorationShadow) {
         if (AbstractClient *c = qobject_cast<AbstractClient*>(m_topLevel)) {