diff --git a/src/effect/effectwindow.cpp b/src/effect/effectwindow.cpp
index b8a8dff8cf..b66859d3ce 100644
--- a/src/effect/effectwindow.cpp
+++ b/src/effect/effectwindow.cpp
@@ -344,11 +344,6 @@ QSizeF EffectWindow::basicUnit() const
     return QSize(1, 1);
 }
 
-QRectF EffectWindow::decorationInnerRect() const
-{
-    return d->m_window->rect() - d->m_window->frameMargins();
-}
-
 KDecoration2::Decoration *EffectWindow::decoration() const
 {
     return d->m_window->decoration();
diff --git a/src/effect/effectwindow.h b/src/effect/effectwindow.h
index df36516fc3..de03a9df5a 100644
--- a/src/effect/effectwindow.h
+++ b/src/effect/effectwindow.h
@@ -222,11 +222,6 @@ class KWIN_EXPORT EffectWindow : public QObject
      * Geometry of the actual window contents inside the whole (including decorations) window.
      */
     Q_PROPERTY(QRectF contentsRect READ contentsRect)
-    /**
-     * Geometry of the transparent rect in the decoration.
-     * May be different from contentsRect if the decoration is extended into the client area.
-     */
-    Q_PROPERTY(QRectF decorationInnerRect READ decorationInnerRect)
     Q_PROPERTY(bool hasDecoration READ hasDecoration)
     Q_PROPERTY(QStringList activities READ activities)
     Q_PROPERTY(bool onCurrentActivity READ isOnCurrentActivity)
@@ -423,12 +418,6 @@ public:
      * Geometry of the actual window contents inside the whole (including decorations) window.
      */
     QRectF contentsRect() const;
-    /**
-     * Geometry of the transparent rect in the decoration.
-     * May be different from contentsRect() if the decoration is extended into the client area.
-     * @since 4.5
-     */
-    QRectF decorationInnerRect() const;
     bool hasDecoration() const;
     bool decorationHasAlpha() const;
     /**
diff --git a/src/plugins/backgroundcontrast/contrast.cpp b/src/plugins/backgroundcontrast/contrast.cpp
index 20a04ceb8e..9330939c3c 100644
--- a/src/plugins/backgroundcontrast/contrast.cpp
+++ b/src/plugins/backgroundcontrast/contrast.cpp
@@ -305,11 +305,11 @@ QRegion ContrastEffect::contrastRegion(const EffectWindow *w) const
     if (const auto it = m_windowData.find(w); it != m_windowData.end()) {
         const QRegion &appRegion = it->second.contrastRegion;
         if (!appRegion.isEmpty()) {
-            region += appRegion.translated(w->contentsRect().topLeft().toPoint()) & w->decorationInnerRect().toRect();
+            region += appRegion.translated(w->contentsRect().topLeft().toPoint()) & w->contentsRect().toRect();
         } else {
-            // An empty region means that the blur effect should be enabled
+            // An empty region means that the contrast effect should be enabled
             // for the whole window.
-            region = w->decorationInnerRect().toRect();
+            region = w->contentsRect().toRect();
         }
     }
 
diff --git a/src/plugins/blur/blur.cpp b/src/plugins/blur/blur.cpp
index fff1cabe81..96a9174130 100644
--- a/src/plugins/blur/blur.cpp
+++ b/src/plugins/blur/blur.cpp
@@ -385,7 +385,7 @@ QRegion BlurEffect::decorationBlurRegion(const EffectWindow *w) const
         return QRegion();
     }
 
-    QRegion decorationRegion = QRegion(w->decoration()->rect()) - w->decorationInnerRect().toRect();
+    QRegion decorationRegion = QRegion(w->decoration()->rect()) - w->contentsRect().toRect();
     //! we return only blurred regions that belong to decoration region
     return decorationRegion.intersected(w->decoration()->blurRegion());
 }
@@ -403,7 +403,7 @@ QRegion BlurEffect::blurRegion(EffectWindow *w) const
                 // for the whole window.
                 region = w->contentsRect().toRect();
             } else {
-                region = content->translated(w->contentsRect().topLeft().toPoint()) & w->decorationInnerRect().toRect();
+                region = content->translated(w->contentsRect().topLeft().toPoint()) & w->contentsRect().toRect();
             }
             if (frame.has_value()) {
                 region += frame.value();