diff --git a/composite.cpp b/composite.cpp
index 9983ed3a84..43e5ead886 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -133,6 +133,7 @@ Compositor::Compositor(QObject* workspace)
 
 Compositor::~Compositor()
 {
+    emit aboutToDestroy();
     finish();
     deleteUnusedSupportProperties();
     delete cm_selection;
diff --git a/composite.h b/composite.h
index 571eaba783..3a2a2a21ac 100644
--- a/composite.h
+++ b/composite.h
@@ -185,6 +185,7 @@ public Q_SLOTS:
 
 Q_SIGNALS:
     void compositingToggled(bool active);
+    void aboutToDestroy();
 
 protected:
     void timerEvent(QTimerEvent *te);
diff --git a/decorations/settings.cpp b/decorations/settings.cpp
index 2e08dcd366..d8bd039a98 100644
--- a/decorations/settings.cpp
+++ b/decorations/settings.cpp
@@ -39,7 +39,7 @@ SettingsImpl::SettingsImpl(KDecoration2::DecorationSettings *parent)
 {
     readSettings();
 
-    connect(Compositor::self(), &Compositor::compositingToggled,
+    auto c = connect(Compositor::self(), &Compositor::compositingToggled,
             parent, &KDecoration2::DecorationSettings::alphaChannelSupportedChanged);
     connect(VirtualDesktopManager::self(), &VirtualDesktopManager::countChanged, this,
         [parent](uint previous, uint current) {
@@ -49,6 +49,12 @@ SettingsImpl::SettingsImpl(KDecoration2::DecorationSettings *parent)
             emit parent->onAllDesktopsAvailableChanged(current > 1);
         }
     );
+    // prevent changes in Decoration due to Compositor being destroyed
+    connect(Compositor::self(), &Compositor::aboutToDestroy, this,
+        [this, c] {
+            disconnect(c);
+        }
+    );
 }
 
 SettingsImpl::~SettingsImpl() = default;