diff --git a/autotests/wayland/kwin_wayland_test.cpp b/autotests/wayland/kwin_wayland_test.cpp
index eec0f56830..ba37dfa6a9 100644
--- a/autotests/wayland/kwin_wayland_test.cpp
+++ b/autotests/wayland/kwin_wayland_test.cpp
@@ -62,6 +62,7 @@ WaylandTestApplication::~WaylandTestApplication()
     if (x11Connection()) {
         Xcb::setInputFocus(XCB_INPUT_FOCUS_POINTER_ROOT);
         destroyAtoms();
+        emit x11ConnectionAboutToBeDestroyed();
         xcb_disconnect(x11Connection());
         setX11Connection(nullptr);
     }
diff --git a/composite.cpp b/composite.cpp
index 77d66d4ae5..c921c87e45 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -128,6 +128,12 @@ Compositor::Compositor(QObject* workspace)
                 }
             }, Qt::QueuedConnection
         );
+        connect(kwinApp(), &Application::x11ConnectionAboutToBeDestroyed, this,
+            [this] {
+                delete cm_selection;
+                cm_selection = nullptr;
+            }
+        );
     } else {
         // delay the call to setup by one event cycle
         // The ctor of this class is invoked from the Workspace ctor, that means before
diff --git a/main.h b/main.h
index 4a2a7e994f..a345cd36ca 100644
--- a/main.h
+++ b/main.h
@@ -152,6 +152,7 @@ public:
 
 Q_SIGNALS:
     void x11ConnectionChanged();
+    void x11ConnectionAboutToBeDestroyed();
     void workspaceCreated();
     void screensCreated();
     void virtualTerminalCreated();
diff --git a/main_wayland.cpp b/main_wayland.cpp
index 93831d1921..21aeebb6a1 100644
--- a/main_wayland.cpp
+++ b/main_wayland.cpp
@@ -86,6 +86,7 @@ ApplicationWayland::~ApplicationWayland()
     if (x11Connection()) {
         Xcb::setInputFocus(XCB_INPUT_FOCUS_POINTER_ROOT);
         destroyAtoms();
+        emit x11ConnectionAboutToBeDestroyed();
         xcb_disconnect(x11Connection());
         setX11Connection(nullptr);
     }