diff --git a/effects.cpp b/effects.cpp
index 6c252c9e65..b80be3d509 100644
--- a/effects.cpp
+++ b/effects.cpp
@@ -532,6 +532,13 @@ bool EffectsHandlerImpl::hasKeyboardGrab() const
     return keyboard_grab_effect != NULL;
 }
 
+void EffectsHandlerImpl::desktopResized(const QSize &size)
+{
+    scene->screenGeometryChanged(size);
+    emit screenGeometryChanged(size);
+    Workspace::self()->addRepaintFull();
+}
+
 void EffectsHandlerImpl::slotPropertyNotify(Toplevel* t, long int atom)
 {
     if (!registered_atoms.contains(atom))
@@ -1243,6 +1250,21 @@ bool EffectsHandlerImpl::isEffectLoaded(const QString& name)
     return false;
 }
 
+void EffectsHandlerImpl::reloadEffect(Effect *effect)
+{
+    QString effectName;
+    for (QVector< EffectPair >::iterator it = loaded_effects.begin(); it != loaded_effects.end(); ++it) {
+        if ((*it).second == effect) {
+            effectName = (*it).first;
+            break;
+        }
+    }
+    if (!effectName.isNull()) {
+        unloadEffect(effectName);
+        loadEffect(effectName);
+    }
+}
+
 void EffectsHandlerImpl::effectsChanged()
 {
     loaded_effects.clear();
diff --git a/effects.h b/effects.h
index f4ad2fbd85..4d49316856 100644
--- a/effects.h
+++ b/effects.h
@@ -160,7 +160,9 @@ public:
     bool borderActivated(ElectricBorder border);
     void grabbedKeyboardEvent(QKeyEvent* e);
     bool hasKeyboardGrab() const;
+    void desktopResized(const QSize &size);
 
+    virtual void reloadEffect(Effect *effect);
     bool loadEffect(const QString& name, bool checkDefault = false);
     void toggleEffect(const QString& name);
     void unloadEffect(const QString& name);
diff --git a/effects/blur/blur.cpp b/effects/blur/blur.cpp
index a25355b01b..06c685450d 100644
--- a/effects/blur/blur.cpp
+++ b/effects/blur/blur.cpp
@@ -63,6 +63,7 @@ BlurEffect::BlurEffect()
     connect(effects, SIGNAL(windowAdded(EffectWindow*)), this, SLOT(slotWindowAdded(EffectWindow*)));
     connect(effects, SIGNAL(windowDeleted(EffectWindow*)), this, SLOT(slotWindowDeleted(EffectWindow*)));
     connect(effects, SIGNAL(propertyNotify(EffectWindow*,long)), this, SLOT(slotPropertyNotify(EffectWindow*,long)));
+    connect(effects, SIGNAL(screenGeometryChanged(QSize)), this, SLOT(slotScreenGeometryChanged()));
 }
 
 BlurEffect::~BlurEffect()
@@ -76,6 +77,11 @@ BlurEffect::~BlurEffect()
     delete target;
 }
 
+void BlurEffect::slotScreenGeometryChanged()
+{
+    effects->reloadEffect(this);
+}
+
 void BlurEffect::reconfigure(ReconfigureFlags flags)
 {
     Q_UNUSED(flags)
diff --git a/effects/blur/blur.h b/effects/blur/blur.h
index ea5f01daba..65ba3811ca 100644
--- a/effects/blur/blur.h
+++ b/effects/blur/blur.h
@@ -52,6 +52,7 @@ public Q_SLOTS:
     void slotWindowAdded(EffectWindow *w);
     void slotWindowDeleted(EffectWindow *w);
     void slotPropertyNotify(EffectWindow *w, long atom);
+    void slotScreenGeometryChanged();
 
 private:
     QRect expand(const QRect &rect) const;
diff --git a/geometry.cpp b/geometry.cpp
index a414e263d1..bfc304bb2e 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -76,8 +76,9 @@ void Workspace::desktopResized()
 #ifdef KWIN_BUILD_SCREENEDGES
     m_screenEdge.update(true);
 #endif
-    if (compositing())
-        compositeResetTimer.start(0);
+    if (effects) {
+        static_cast<EffectsHandlerImpl*>(effects)->desktopResized(geom.size());
+    }
 }
 
 void Workspace::saveOldScreenSizes()
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
index 9f239c845a..b7d8184a22 100644
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -795,6 +795,16 @@ public:
     virtual EffectFrame* effectFrame(EffectFrameStyle style, bool staticSize = true,
                                      const QPoint& position = QPoint(-1, -1), Qt::Alignment alignment = Qt::AlignCenter) const = 0;
 
+    /**
+     * Allows an effect to trigger a reload of itself.
+     * This can be used by an effect which needs to be reloaded when screen geometry changes.
+     * It is possible that the effect cannot be loaded again as it's supported method does no longer
+     * hold.
+     * @param effect The effect to reload
+     * @since 4.8
+     **/
+    virtual void reloadEffect(Effect *effect) = 0;
+
     /**
      * Sends message over DCOP to reload given effect.
      * @param effectname effect's name without "kwin4_effect_" prefix.
@@ -1033,6 +1043,15 @@ Q_SIGNALS:
      **/
     void hideOutline();
 
+    /**
+     * Signal emitted after the screen geometry changed (e.g. add of a monitor).
+     * Effects using displayWidth()/displayHeight() to cache information should
+     * react on this signal and update the caches.
+     * @param size The new screen size
+     * @since 4.8
+     **/
+    void screenGeometryChanged(const QSize &size);
+
 protected:
     QVector< EffectPair > loaded_effects;
     QHash< QString, KLibrary* > effect_libraries;
diff --git a/libkwineffects/kwinglutils.cpp b/libkwineffects/kwinglutils.cpp
index 2a3740ee59..4102d3f1b4 100644
--- a/libkwineffects/kwinglutils.cpp
+++ b/libkwineffects/kwinglutils.cpp
@@ -689,6 +689,20 @@ GLShader *ShaderManager::pushShader(ShaderType type, bool reset)
     return shader;
 }
 
+void ShaderManager::resetAllShaders()
+{
+    if (!m_inited || !m_valid) {
+        return;
+    }
+    pushShader(SimpleShader, true);
+    pushShader(GenericShader, true);
+    pushShader(ColorShader, true);
+    popShader();
+    popShader();
+    popShader();
+}
+
+
 void ShaderManager::pushShader(GLShader *shader)
 {
     // only bind shader if it is not already bound
diff --git a/libkwineffects/kwinglutils.h b/libkwineffects/kwinglutils.h
index 876cf3ad7f..c39f2dc361 100644
--- a/libkwineffects/kwinglutils.h
+++ b/libkwineffects/kwinglutils.h
@@ -321,6 +321,13 @@ public:
      **/
     void popShader();
 
+    /**
+     * Resets all shaders to the default uniform values.
+     * Only built in shaders are changed.
+     * @since 4.8
+     **/
+    void resetAllShaders();
+
     /**
      * Creates a GLShader with a built-in vertex shader and a custom fragment shader.
      * @param vertex The generic vertex shader
diff --git a/overlaywindow.cpp b/overlaywindow.cpp
index 43f1a52a1f..528dade5df 100644
--- a/overlaywindow.cpp
+++ b/overlaywindow.cpp
@@ -120,6 +120,13 @@ void OverlayWindow::setShape(const QRegion& reg)
     m_shape = reg;
 }
 
+void OverlayWindow::resize(const QSize &size)
+{
+    assert(m_window != None);
+    XResizeWindow(display(), m_window, size.width(), size.height());
+    setShape(QRegion(0, 0, size.width(), size.height()));
+}
+
 bool OverlayWindow::isVisible() const
 {
     return m_visible;
diff --git a/overlaywindow.h b/overlaywindow.h
index 14d2d58334..d2d999523b 100644
--- a/overlaywindow.h
+++ b/overlaywindow.h
@@ -37,6 +37,7 @@ public:
     void show();
     void hide(); // hides and resets overlay window
     void setShape(const QRegion& reg);
+    void resize(const QSize &size);
     /// Destroys XComposite overlay window
     void destroy();
     Window window() const;
diff --git a/scene.cpp b/scene.cpp
index 4589aa56b7..ef1058dfee 100644
--- a/scene.cpp
+++ b/scene.cpp
@@ -426,6 +426,11 @@ OverlayWindow* Scene::overlayWindow()
     return m_overlayWindow;
 }
 
+void Scene::screenGeometryChanged(const QSize &size)
+{
+    m_overlayWindow->resize(size);
+}
+
 //****************************************
 // Scene::Window
 //****************************************
diff --git a/scene.h b/scene.h
index 17be282b5a..c227352522 100644
--- a/scene.h
+++ b/scene.h
@@ -60,6 +60,13 @@ public:
     virtual void windowAdded(Toplevel*) = 0;
     // a window has been destroyed
     virtual void windowDeleted(Deleted*) = 0;
+    /**
+     * Method invoked when the screen geometry is changed.
+     * Reimplementing classes should also invoke the parent method
+     * as it takes care of resizing the overlay window.
+     * @param size The new screen geometry size
+     **/
+    virtual void screenGeometryChanged(const QSize &size);
     // Flags controlling how painting is done.
     enum {
         // Window (or at least part of it) will be painted opaque.
diff --git a/scene_opengl.h b/scene_opengl.h
index 9c0b057f96..5bc9d5e936 100644
--- a/scene_opengl.h
+++ b/scene_opengl.h
@@ -53,6 +53,7 @@ public:
     virtual void paint(QRegion damage, ToplevelList windows);
     virtual void windowAdded(Toplevel*);
     virtual void windowDeleted(Deleted*);
+    virtual void screenGeometryChanged(const QSize &size);
 
 protected:
     virtual void paintGenericScreen(int mask, ScreenPaintData data);
@@ -70,6 +71,9 @@ private:
     bool initBufferConfigs();
     bool initDrawableConfigs();
     void waitSync();
+#ifndef KWIN_HAVE_OPENGLES
+    void setupModelViewProjectionMatrix();
+#endif
     void flushBuffer(int mask, QRegion damage);
     GC gcroot;
     class FBConfigInfo
@@ -86,6 +90,7 @@ private:
 #ifndef KWIN_HAVE_OPENGLES
     Drawable buffer;
     GLXFBConfig fbcbuffer;
+    bool m_resetModelViewProjectionMatrix;
 #endif
     static bool db;
 #ifndef KWIN_HAVE_OPENGLES
diff --git a/scene_opengl_egl.cpp b/scene_opengl_egl.cpp
index 7a198b0f6f..90841338f5 100644
--- a/scene_opengl_egl.cpp
+++ b/scene_opengl_egl.cpp
@@ -218,6 +218,13 @@ void SceneOpenGL::flushBuffer(int mask, QRegion damage)
     XFlush(display());
 }
 
+void SceneOpenGL::screenGeometryChanged(const QSize &size)
+{
+    glViewport(0,0, size.width(), size.height());
+    Scene::screenGeometryChanged(size);
+    ShaderManager::instance()->resetAllShaders();
+}
+
 //****************************************
 // SceneOpenGL::Texture
 //****************************************
diff --git a/scene_opengl_glx.cpp b/scene_opengl_glx.cpp
index 35f04494de..d978605bb9 100644
--- a/scene_opengl_glx.cpp
+++ b/scene_opengl_glx.cpp
@@ -38,6 +38,7 @@ GLXDrawable SceneOpenGL::last_pixmap = None;
 SceneOpenGL::SceneOpenGL(Workspace* ws)
     : Scene(ws)
     , init_ok(false)
+    , m_resetModelViewProjectionMatrix(true)
 {
     initGLX();
     // check for FBConfig support
@@ -100,23 +101,7 @@ SceneOpenGL::SceneOpenGL(Workspace* ws)
     }
 
     // OpenGL scene setup
-    glMatrixMode(GL_PROJECTION);
-    glLoadIdentity();
-    float fovy = 60.0f;
-    float aspect = 1.0f;
-    float zNear = 0.1f;
-    float zFar = 100.0f;
-    float ymax = zNear * tan(fovy  * M_PI / 360.0f);
-    float ymin = -ymax;
-    float xmin =  ymin * aspect;
-    float xmax = ymax * aspect;
-    // swap top and bottom to have OpenGL coordinate system match X system
-    glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
-    glMatrixMode(GL_MODELVIEW);
-    glLoadIdentity();
-    float scaleFactor = 1.1 * tan(fovy * M_PI / 360.0f) / ymax;
-    glTranslatef(xmin * scaleFactor, ymax * scaleFactor, -1.1);
-    glScalef((xmax - xmin)*scaleFactor / displayWidth(), -(ymax - ymin)*scaleFactor / displayHeight(), 0.001);
+    setupModelViewProjectionMatrix();
     if (checkGLError("Init")) {
         kError(1212) << "OpenGL compositing setup failed";
         return; // error
@@ -152,6 +137,28 @@ SceneOpenGL::~SceneOpenGL()
     checkGLError("Cleanup");
 }
 
+void SceneOpenGL::setupModelViewProjectionMatrix()
+{
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    float fovy = 60.0f;
+    float aspect = 1.0f;
+    float zNear = 0.1f;
+    float zFar = 100.0f;
+    float ymax = zNear * tan(fovy  * M_PI / 360.0f);
+    float ymin = -ymax;
+    float xmin =  ymin * aspect;
+    float xmax = ymax * aspect;
+    // swap top and bottom to have OpenGL coordinate system match X system
+    glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
+    glMatrixMode(GL_MODELVIEW);
+    glLoadIdentity();
+    float scaleFactor = 1.1 * tan(fovy * M_PI / 360.0f) / ymax;
+    glTranslatef(xmin * scaleFactor, ymax * scaleFactor, -1.1);
+    glScalef((xmax - xmin)*scaleFactor / displayWidth(), -(ymax - ymin)*scaleFactor / displayHeight(), 0.001);
+    m_resetModelViewProjectionMatrix = false;
+}
+
 bool SceneOpenGL::initTfp()
 {
     if (glXBindTexImageEXT == NULL || glXReleaseTexImageEXT == NULL)
@@ -451,6 +458,10 @@ void SceneOpenGL::paint(QRegion damage, ToplevelList toplevels)
 
     grabXServer();
     glXWaitX();
+    if (m_resetModelViewProjectionMatrix) {
+        // reset model view projection matrix if required
+        setupModelViewProjectionMatrix();
+    }
     glPushMatrix();
     int mask = 0;
 #ifdef CHECK_GL_ERROR
@@ -558,6 +569,33 @@ void SceneOpenGL::flushBuffer(int mask, QRegion damage)
     }
 }
 
+void SceneOpenGL::screenGeometryChanged(const QSize &size)
+{
+    Scene::screenGeometryChanged(size);
+    glViewport(0,0, size.width(), size.height());
+    if (m_overlayWindow->window() == None) {
+        glXMakeCurrent(display(), None, NULL);
+        glXDestroyPixmap(display(), glxbuffer);
+        XFreePixmap(display(), buffer);
+        XVisualInfo* visual = glXGetVisualFromFBConfig(display(), fbcbuffer);
+        buffer = XCreatePixmap(display(), rootWindow(), size.width(), size.height(), visual->depth);
+        XFree(visual);
+        glxbuffer = glXCreatePixmap(display(), fbcbuffer, buffer, NULL);
+        glXMakeCurrent(display(), glxbuffer, ctxbuffer);
+        // TODO: there seems some bug, some clients become black until an eg. un/remap - could be a general pixmap buffer issue, though
+    }
+    else {
+        glXMakeCurrent(display(), None, NULL); // deactivate context ////
+        XMoveResizeWindow(display(), buffer, 0,0, size.width(), size.height());
+        m_overlayWindow->setup(buffer);
+        XSync(display(), false);  // ensure X11 stuff has applied ////
+        glXMakeCurrent(display(), glxbuffer, ctxbuffer); // reactivate context ////
+        glViewport(0,0, size.width(), size.height()); // adjust viewport last - should btw. be superflous on the Pixmap buffer - iirc glXCreatePixmap sets the context anyway. ////
+    }
+    ShaderManager::instance()->resetAllShaders();
+    m_resetModelViewProjectionMatrix = true;
+}
+
 //****************************************
 // SceneOpenGL::Texture
 //****************************************
diff --git a/scene_xrender.cpp b/scene_xrender.cpp
index a2f2f2a504..dea424a6e2 100644
--- a/scene_xrender.cpp
+++ b/scene_xrender.cpp
@@ -99,8 +99,32 @@ SceneXrender::SceneXrender(Workspace* ws)
         kError(1212) << "No XFixes v3+ extension available";
         return;
     }
+    initXRender(true);
+}
+
+SceneXrender::~SceneXrender()
+{
+    if (!init_ok) {
+        // TODO this probably needs to clean up whatever has been created until the failure
+        m_overlayWindow->destroy();
+        return;
+    }
+    XRenderFreePicture(display(), front);
+    XRenderFreePicture(display(), buffer);
+    buffer = None;
+    m_overlayWindow->destroy();
+    foreach (Window * w, windows)
+    delete w;
+}
+
+void SceneXrender::initXRender(bool createOverlay)
+{
+    init_ok = false;
+    if (front != None)
+        XRenderFreePicture(display(), front);
     KXErrorHandler xerr;
-    if (m_overlayWindow->create()) {
+    bool haveOverlay = createOverlay ? m_overlayWindow->create() : (m_overlayWindow->window() != None);
+    if (haveOverlay) {
         m_overlayWindow->setup(None);
         XWindowAttributes attrs;
         XGetWindowAttributes(display(), m_overlayWindow->window(), &attrs);
@@ -129,21 +153,6 @@ SceneXrender::SceneXrender(Workspace* ws)
     init_ok = true;
 }
 
-SceneXrender::~SceneXrender()
-{
-    if (!init_ok) {
-        // TODO this probably needs to clean up whatever has been created until the failure
-        m_overlayWindow->destroy();
-        return;
-    }
-    XRenderFreePicture(display(), front);
-    XRenderFreePicture(display(), buffer);
-    buffer = None;
-    m_overlayWindow->destroy();
-    foreach (Window * w, windows)
-    delete w;
-}
-
 bool SceneXrender::initFailed() const
 {
     return !init_ok;
@@ -153,6 +162,8 @@ bool SceneXrender::initFailed() const
 // so it is done manually using this buffer,
 void SceneXrender::createBuffer()
 {
+    if (buffer != None)
+        XRenderFreePicture(display(), buffer);
     Pixmap pixmap = XCreatePixmap(display(), rootWindow(), displayWidth(), displayHeight(), DefaultDepth(display(), DefaultScreen(display())));
     buffer = XRenderCreatePicture(display(), pixmap, format, 0, 0);
     XFreePixmap(display(), pixmap);   // The picture owns the pixmap now
@@ -774,6 +785,12 @@ XRenderComposite(display(), PictOpOver, _PART_->x11PictureHandle(), decorationAl
     }
 }
 
+void SceneXrender::screenGeometryChanged(const QSize &size)
+{
+    Scene::screenGeometryChanged(size);
+    initXRender(false);
+}
+
 //****************************************
 // SceneXrender::EffectFrame
 //****************************************
diff --git a/scene_xrender.h b/scene_xrender.h
index 23ff2addbd..c181f0dca9 100644
--- a/scene_xrender.h
+++ b/scene_xrender.h
@@ -49,6 +49,7 @@ public:
     virtual void paint(QRegion damage, ToplevelList windows);
     virtual void windowAdded(Toplevel*);
     virtual void windowDeleted(Deleted*);
+    virtual void screenGeometryChanged(const QSize &size);
     Picture bufferPicture();
 protected:
     virtual void paintBackground(QRegion region);
@@ -61,6 +62,7 @@ private:
     void paintTransformedScreen(int mask);
     void createBuffer();
     void flushBuffer(int mask, QRegion damage);
+    void initXRender(bool createOverlay);
     XRenderPictFormat* format;
     Picture front;
     static Picture buffer;