diff --git a/effects/diminactive/diminactive.cpp b/effects/diminactive/diminactive.cpp
index aae2c8b1b2..69ba653117 100644
--- a/effects/diminactive/diminactive.cpp
+++ b/effects/diminactive/diminactive.cpp
@@ -372,6 +372,12 @@ void DimInactiveEffect::windowClosed(EffectWindow *w)
 void DimInactiveEffect::windowDeleted(EffectWindow *w)
 {
     m_forceDim.remove(w);
+
+    // FIXME: Sometimes we can miss the window close signal because KWin
+    // can activate a window that is not ready for painting and the window
+    // gets destroyed immediately. So, we have to remove active transitions
+    // for that window here, otherwise we'll crash in postPaintScreen.
+    m_transitions.remove(w);
 }
 
 void DimInactiveEffect::activeFullScreenEffectChanged()
diff --git a/plugins/qpa/integration.cpp b/plugins/qpa/integration.cpp
index 055b8fb133..d934b97601 100644
--- a/plugins/qpa/integration.cpp
+++ b/plugins/qpa/integration.cpp
@@ -205,11 +205,17 @@ QPlatformOpenGLContext *Integration::createPlatformOpenGLContext(QOpenGLContext
 void Integration::initScreens()
 {
     QVector<Screen*> newScreens;
+    newScreens.reserve(qMax(screens()->count(), 1));
     for (int i = 0; i < screens()->count(); i++) {
         auto screen = new Screen(i);
         screenAdded(screen);
         newScreens << screen;
     }
+    if (newScreens.isEmpty()) {
+        auto dummyScreen = new Screen(-1);
+        screenAdded(dummyScreen);
+        newScreens << dummyScreen;
+    }
     while (!m_screens.isEmpty()) {
         destroyScreen(m_screens.takeLast());
     }
diff --git a/useractions.cpp b/useractions.cpp
index f3ca0f90bf..1d10f7a228 100644
--- a/useractions.cpp
+++ b/useractions.cpp
@@ -178,7 +178,7 @@ void UserActionsMenu::show(const QRect &pos, const QWeakPointer<AbstractClient>
             }
         }
         if (!m_client.isNull())
-            m_client.data()->blockActivityUpdates(true);
+            m_client.data()->blockActivityUpdates(false);
     }
 }