diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -1750,23 +1750,23 @@
      * @param w The window whose the keep above state was changed.
      * @since 5.15
      **/
-    void windowKeepAboveChanged(EffectWindow *w);
+    void windowKeepAboveChanged(KWin::EffectWindow *w);
 
     /**
      * This signal is emitted when the keep below state of @p was changed.
      *
      * @param w The window whose the keep below state was changed.
      * @since 5.15
      **/
-    void windowKeepBelowChanged(EffectWindow *w);
+    void windowKeepBelowChanged(KWin::EffectWindow *w);
 
     /**
      * This signal is emitted when the full screen state of @p w was changed.
      *
      * @param w The window whose the full screen state was changed.
      * @since 5.15
      **/
-    void windowFullScreenChanged(EffectWindow *w);
+    void windowFullScreenChanged(KWin::EffectWindow *w);
 
 protected:
     QVector< EffectPair > loaded_effects;