diff --git a/effects/slidingpopups/slidingpopups.h b/effects/slidingpopups/slidingpopups.h
--- a/effects/slidingpopups/slidingpopups.h
+++ b/effects/slidingpopups/slidingpopups.h
@@ -54,10 +54,10 @@
     int slideInDuration() const;
     int slideOutDuration() const;
 
-public Q_SLOTS:
-    void slotWindowAdded(KWin::EffectWindow *c);
-    void slotWindowDeleted(KWin::EffectWindow *w);
-    void slotPropertyNotify(KWin::EffectWindow *w, long a);
+private Q_SLOTS:
+    void slotWindowAdded(EffectWindow *w);
+    void slotWindowDeleted(EffectWindow *w);
+    void slotPropertyNotify(EffectWindow *w, long a);
     void slotWaylandSlideOnShowChanged(EffectWindow* w);
 
     void slideIn(EffectWindow *w);
diff --git a/effects/slidingpopups/slidingpopups.cpp b/effects/slidingpopups/slidingpopups.cpp
--- a/effects/slidingpopups/slidingpopups.cpp
+++ b/effects/slidingpopups/slidingpopups.cpp
@@ -42,10 +42,10 @@
     mSlideLength = QFontMetrics(qApp->font()).height() * 8;
 
     mAtom = effects->announceSupportProperty("_KDE_SLIDE", this);
-    connect(effects, SIGNAL(windowAdded(KWin::EffectWindow*)), this, SLOT(slotWindowAdded(KWin::EffectWindow*)));
+    connect(effects, &EffectsHandler::windowAdded, this, &SlidingPopupsEffect::slotWindowAdded);
     connect(effects, &EffectsHandler::windowClosed, this, &SlidingPopupsEffect::slideOut);
-    connect(effects, SIGNAL(windowDeleted(KWin::EffectWindow*)), this, SLOT(slotWindowDeleted(KWin::EffectWindow*)));
-    connect(effects, SIGNAL(propertyNotify(KWin::EffectWindow*,long)), this, SLOT(slotPropertyNotify(KWin::EffectWindow*,long)));
+    connect(effects, &EffectsHandler::windowDeleted, this, &SlidingPopupsEffect::slotWindowDeleted);
+    connect(effects, &EffectsHandler::propertyNotify, this, &SlidingPopupsEffect::slotPropertyNotify);
     connect(effects, &EffectsHandler::windowShown, this, &SlidingPopupsEffect::slideIn);
     connect(effects, &EffectsHandler::windowHidden, this, &SlidingPopupsEffect::slideOut);
     connect(effects, &EffectsHandler::xcbConnectionChanged, this,