diff --git a/composite.cpp b/composite.cpp
--- a/composite.cpp
+++ b/composite.cpp
@@ -960,13 +960,6 @@
 
     Compositor::self()->scene()->addToplevel(this);
 
-    // With unmanaged windows there is a race condition between the client painting the window
-    // and us setting up damage tracking.  If the client wins we won't get a damage event even
-    // though the window has been painted.  To avoid this we mark the whole window as damaged
-    // and schedule a repaint immediately after creating the damage object.
-    if (dynamic_cast<Unmanaged*>(this))
-        addDamageFull();
-
     return true;
 }
 
diff --git a/unmanaged.h b/unmanaged.h
--- a/unmanaged.h
+++ b/unmanaged.h
@@ -49,6 +49,8 @@
     NET::WindowType windowType(bool direct = false, int supported_types = 0) const;
     bool isOutline() const override;
 
+    bool setupCompositing() override;
+
 public Q_SLOTS:
     void release(ReleaseReason releaseReason = ReleaseReason::Release);
 protected:
diff --git a/unmanaged.cpp b/unmanaged.cpp
--- a/unmanaged.cpp
+++ b/unmanaged.cpp
@@ -185,5 +185,20 @@
     return nullptr;
 }
 
+bool Unmanaged::setupCompositing()
+{
+    if (!Toplevel::setupCompositing()) {
+        return false;
+    }
+
+    // With unmanaged windows there is a race condition between the client painting the window
+    // and us setting up damage tracking.  If the client wins we won't get a damage event even
+    // though the window has been painted.  To avoid this we mark the whole window as damaged
+    // and schedule a repaint immediately after creating the damage object.
+    addDamageFull();
+
+    return true;
+}
+
 } // namespace