diff --git a/src/plugins/blur/blur.cpp b/src/plugins/blur/blur.cpp
index 9a3e19f481..db1409ca5d 100644
--- a/src/plugins/blur/blur.cpp
+++ b/src/plugins/blur/blur.cpp
@@ -334,9 +334,9 @@ void BlurEffect::updateBlurRegion(EffectWindow *w)
     }
 
     if (valid) {
-        blurRegions[w] = region;
+        m_windows[w].region = region;
     } else {
-        blurRegions.remove(w);
+        m_windows.remove(w);
     }
 }
 
@@ -361,7 +361,7 @@ void BlurEffect::slotWindowAdded(EffectWindow *w)
 
 void BlurEffect::slotWindowDeleted(EffectWindow *w)
 {
-    blurRegions.remove(w);
+    m_windows.remove(w);
     auto it = windowBlurChangedConnections.find(w);
     if (it == windowBlurChangedConnections.end()) {
         return;
@@ -471,12 +471,12 @@ QRegion BlurEffect::expand(const QRegion &region) const
     return expanded;
 }
 
-QRegion BlurEffect::blurRegion(const EffectWindow *w) const
+QRegion BlurEffect::blurRegion(EffectWindow *w) const
 {
     QRegion region;
 
-    if (auto it = blurRegions.find(w); it != blurRegions.end()) {
-        const QRegion &appRegion = *it;
+    if (auto it = m_windows.find(w); it != m_windows.end()) {
+        const QRegion &appRegion = it->region;
         if (!appRegion.isEmpty()) {
             if (w->decorationHasAlpha() && decorationSupportsBlurBehind(w)) {
                 region = decorationBlurRegion(w);
diff --git a/src/plugins/blur/blur.h b/src/plugins/blur/blur.h
index 9ca5f607ba..78fb789225 100644
--- a/src/plugins/blur/blur.h
+++ b/src/plugins/blur/blur.h
@@ -27,6 +27,11 @@ static const int borderSize = 5;
 
 class BlurShader;
 
+struct BlurData
+{
+    QRegion region;
+};
+
 class BlurEffect : public KWin::Effect
 {
     Q_OBJECT
@@ -78,7 +83,7 @@ private:
     QRegion expand(const QRegion &region) const;
     void initBlurStrengthValues();
     bool updateTexture(EffectScreen *screen, const RenderTarget &renderTarget);
-    QRegion blurRegion(const EffectWindow *w) const;
+    QRegion blurRegion(EffectWindow *w) const;
     QRegion decorationBlurRegion(const EffectWindow *w) const;
     bool decorationSupportsBlurBehind(const EffectWindow *w) const;
     bool shouldBlur(const EffectWindow *w, int mask, const WindowPaintData &data) const;
@@ -132,7 +137,7 @@ private:
     QVector<BlurValuesStruct> blurStrengthValues;
 
     QMap<EffectWindow *, QMetaObject::Connection> windowBlurChangedConnections;
-    QMap<const EffectWindow *, QRegion> blurRegions;
+    QHash<EffectWindow *, BlurData> m_windows;
 
     static KWaylandServer::BlurManagerInterface *s_blurManager;
     static QTimer *s_blurManagerRemoveTimer;