diff --git a/effects.cpp b/effects.cpp
--- a/effects.cpp
+++ b/effects.cpp
@@ -620,7 +620,11 @@
 
 void EffectsHandlerImpl::setActiveFullScreenEffect(Effect* e)
 {
+    if (fullscreen_effect == e) {
+        return;
+    }
     fullscreen_effect = e;
+    emit activeFullScreenEffectChanged();
 }
 
 Effect* EffectsHandlerImpl::activeFullScreenEffect() const
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -1695,6 +1695,15 @@
      **/
     void xcbConnectionChanged();
 
+    /**
+     * This signal is emitted when active fullscreen effect changed.
+     *
+     * @see activeFullScreenEffect
+     * @see setActiveFullScreenEffect
+     * @since 5.14
+     **/
+    void activeFullScreenEffectChanged();
+
 protected:
     QVector< EffectPair > loaded_effects;
     //QHash< QString, EffectFactory* > effect_factories;