diff --git a/effects/slidingpopups/slidingpopups.cpp b/effects/slidingpopups/slidingpopups.cpp
--- a/effects/slidingpopups/slidingpopups.cpp
+++ b/effects/slidingpopups/slidingpopups.cpp
@@ -40,8 +40,6 @@
         display->createSlideManager(this)->create();
     }
 
-    m_slideLength = QFontMetrics(qApp->font()).height() * 8;
-
     m_atom = effects->announceSupportProperty("_KDE_SLIDE", this);
     connect(effects, &EffectsHandler::windowAdded, this, &SlidingPopupsEffect::slotWindowAdded);
     connect(effects, &EffectsHandler::windowClosed, this, &SlidingPopupsEffect::slideOut);
@@ -121,44 +119,47 @@
     }
 
     const AnimationData &animData = m_animationsData[w];
-    const int slideLength = (animData.slideLength > 0) ? animData.slideLength : m_slideLength;
 
     const QRect screenRect = effects->clientArea(FullScreenArea, w->screen(), effects->currentDesktop());
     int splitPoint = 0;
     const QRect geo = w->expandedGeometry();
     const qreal t = (*animationIt).timeLine.value();
 
+    int slideLength = animData.slideLength;
+
+    data.multiplyOpacity(interpolate(0.0, 1.0, t));
+
     switch (animData.location) {
     case Location::Left:
-        if (slideLength < geo.width()) {
-            data.multiplyOpacity(t);
-        }
-        data.translate(-interpolate(qMin(geo.width(), slideLength), 0.0, t));
+        slideLength = (slideLength > 0) ? slideLength : geo.width();
+        slideLength = qMin(geo.width(), slideLength);
+
+        data.translate(-interpolate(slideLength, 0.0, t));
         splitPoint = geo.width() - (geo.x() + geo.width() - screenRect.x() - animData.offset);
         region = QRegion(geo.x() + splitPoint, geo.y(), geo.width() - splitPoint, geo.height());
         break;
     case Location::Top:
-        if (slideLength < geo.height()) {
-            data.multiplyOpacity(t);
-        }
-        data.translate(0.0, -interpolate(qMin(geo.height(), slideLength), 0.0, t));
+        slideLength = (slideLength > 0) ? slideLength : geo.height();
+        slideLength = qMin(geo.height(), slideLength);
+
+        data.translate(0.0, -interpolate(slideLength, 0.0, t));
         splitPoint = geo.height() - (geo.y() + geo.height() - screenRect.y() - animData.offset);
         region = QRegion(geo.x(), geo.y() + splitPoint, geo.width(), geo.height() - splitPoint);
         break;
     case Location::Right:
-        if (slideLength < geo.width()) {
-            data.multiplyOpacity(t);
-        }
-        data.translate(interpolate(qMin(geo.width(), slideLength), 0.0, t));
+        slideLength = (slideLength > 0) ? slideLength : geo.width();
+        slideLength = qMin(geo.width(), slideLength);
+
+        data.translate(interpolate(slideLength, 0.0, t));
         splitPoint = screenRect.x() + screenRect.width() - geo.x() - animData.offset;
         region = QRegion(geo.x(), geo.y(), splitPoint, geo.height());
         break;
     case Location::Bottom:
     default:
-        if (slideLength < geo.height()) {
-            data.multiplyOpacity(t);
-        }
-        data.translate(0.0, interpolate(qMin(geo.height(), slideLength), 0.0, t));
+        slideLength = (slideLength > 0) ? slideLength : geo.height();
+        slideLength = qMin(geo.height(), slideLength);
+
+        data.translate(0.0, interpolate(slideLength, 0.0, t));
         splitPoint = screenRect.y() + screenRect.height() - geo.y() - animData.offset;
         region = QRegion(geo.x(), geo.y(), geo.width(), splitPoint);
     }
@@ -396,7 +397,7 @@
     animation.kind = AnimationKind::In;
     animation.timeLine.setDirection(TimeLine::Forward);
     animation.timeLine.setDuration((*dataIt).slideInDuration);
-    animation.timeLine.setEasingCurve(QEasingCurve::InOutSine);
+    animation.timeLine.setEasingCurve(QEasingCurve::OutExpo);
 
     // If the opposite animation (Out) was active and it had shorter duration,
     // at this point, the timeline can end up in the "done" state. Thus, we have
@@ -435,7 +436,7 @@
     animation.kind = AnimationKind::Out;
     animation.timeLine.setDirection(TimeLine::Backward);
     animation.timeLine.setDuration((*dataIt).slideOutDuration);
-    animation.timeLine.setEasingCurve(QEasingCurve::InOutSine);
+    animation.timeLine.setEasingCurve(QEasingCurve::OutExpo); // basically InQuart, as direction is backwards
 
     // If the opposite animation (In) was active and it had shorter duration,
     // at this point, the timeline can end up in the "done" state. Thus, we have