diff --git a/effects.cpp b/effects.cpp
index 4d612e904a..c8ff646f98 100644
--- a/effects.cpp
+++ b/effects.cpp
@@ -59,9 +59,9 @@ EffectsHandlerImpl::~EffectsHandlerImpl()
     {
     if( keyboard_grab_effect != NULL )
         ungrabKeyboard();
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         unloadEffect( ep.first );
-    foreach( InputWindowPair pos, input_windows )
+    foreach( const InputWindowPair &pos, input_windows )
         XDestroyWindow( display(), pos.second );
     }
 
@@ -73,7 +73,7 @@ void EffectsHandlerImpl::reconfigure()
     KService::List offers = KServiceTypeTrader::self()->query("KWin/Effect");
     QStringList effectsToBeLoaded;
     // First unload necessary effects
-    foreach( KService::Ptr service, offers )
+    foreach( const KService::Ptr &service, offers )
         {
         KPluginInfo plugininfo( service );
         plugininfo.load( conf );
@@ -86,7 +86,7 @@ void EffectsHandlerImpl::reconfigure()
             effectsToBeLoaded.append( plugininfo.pluginName() );
         }
     // Then load those that should be loaded
-    foreach( QString effectName, effectsToBeLoaded )
+    foreach( const QString &effectName, effectsToBeLoaded )
         {
         if( !isEffectLoaded( effectName ))
             {
@@ -180,7 +180,7 @@ void EffectsHandlerImpl::startPaint()
 
 void EffectsHandlerImpl::windowUserMovedResized( EffectWindow* c, bool first, bool last )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowUserMovedResized( c, first, last );
     }
 
@@ -188,50 +188,50 @@ void EffectsHandlerImpl::windowOpacityChanged( EffectWindow* c, double old_opaci
     {
     if( static_cast<EffectWindowImpl*>(c)->window()->opacity() == old_opacity )
         return;
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowOpacityChanged( c, old_opacity );
     }
 
 void EffectsHandlerImpl::windowAdded( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowAdded( c );
     }
 
 void EffectsHandlerImpl::windowDeleted( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowDeleted( c );
     elevated_windows.removeAll( c );
     }
 
 void EffectsHandlerImpl::windowClosed( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowClosed( c );
     }
 
 void EffectsHandlerImpl::windowActivated( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowActivated( c );
     }
 
 void EffectsHandlerImpl::windowMinimized( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowMinimized( c );
     }
 
 void EffectsHandlerImpl::windowUnminimized( EffectWindow* c )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowUnminimized( c );
     }
 
 void EffectsHandlerImpl::desktopChanged( int old )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->desktopChanged( old );
     }
 
@@ -239,7 +239,7 @@ void EffectsHandlerImpl::windowDamaged( EffectWindow* w, const QRect& r )
     {
     if( w == NULL )
         return;
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowDamaged( w, r );
     }
 
@@ -247,25 +247,25 @@ void EffectsHandlerImpl::windowGeometryShapeChanged( EffectWindow* w, const QRec
     {
     if( w == NULL ) // during late cleanup effectWindow() may be already NULL
         return;     // in some functions that may still call this
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->windowGeometryShapeChanged( w, old );
     }
 
 void EffectsHandlerImpl::tabBoxAdded( int mode )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->tabBoxAdded( mode );
     }
 
 void EffectsHandlerImpl::tabBoxClosed()
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->tabBoxClosed();
     }
 
 void EffectsHandlerImpl::tabBoxUpdated()
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->tabBoxUpdated();
     }
 
@@ -282,7 +282,7 @@ Effect* EffectsHandlerImpl::activeFullScreenEffect() const
 bool EffectsHandlerImpl::borderActivated( ElectricBorder border )
     {
     bool ret = false;
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         if( ep.second->borderActivated( border ))
             ret = true; // bail out or tell all?
     return ret;
@@ -292,7 +292,7 @@ void EffectsHandlerImpl::mouseChanged( const QPoint& pos, const QPoint& oldpos,
     Qt::MouseButtons buttons, Qt::MouseButtons oldbuttons,
     Qt::KeyboardModifiers modifiers, Qt::KeyboardModifiers oldmodifiers )
     {
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->mouseChanged( pos, oldpos, buttons, oldbuttons, modifiers, oldmodifiers );
     }
 
@@ -329,7 +329,7 @@ void EffectsHandlerImpl::propertyNotify( EffectWindow* c, long atom )
     {
     if( !registered_atoms.contains( atom ))
         return;
-    foreach( EffectPair ep, loaded_effects )
+    foreach( const EffectPair &ep, loaded_effects )
         ep.second->propertyNotify( c, atom );
     }
 
@@ -583,7 +583,7 @@ Window EffectsHandlerImpl::createInputWindow( Effect* e, int x, int y, int w, in
 
 void EffectsHandlerImpl::destroyInputWindow( Window w )
     {
-    foreach( InputWindowPair pos, input_windows )
+    foreach( const InputWindowPair &pos, input_windows )
         {
         if( pos.second == w )
             {
@@ -599,7 +599,7 @@ bool EffectsHandlerImpl::checkInputWindowEvent( XEvent* e )
     {
     if( e->type != ButtonPress && e->type != ButtonRelease && e->type != MotionNotify )
         return false;
-    foreach( InputWindowPair pos, input_windows )
+    foreach( const InputWindowPair &pos, input_windows )
         {
         if( pos.second == e->xany.window )
             {
@@ -648,7 +648,7 @@ void EffectsHandlerImpl::checkInputWindowStacking()
         return;
     Window* wins = new Window[ input_windows.count() ];
     int pos = 0;
-    foreach( InputWindowPair it, input_windows )
+    foreach( const InputWindowPair &it, input_windows )
         wins[ pos++ ] = it.second;
     XRaiseWindow( display(), wins[ 0 ] );
     XRestackWindows( display(), wins, pos );
@@ -797,7 +797,7 @@ bool EffectsHandlerImpl::loadEffect( const QString& name )
     // TODO: detect circular deps
     KPluginInfo plugininfo( service );
     QStringList dependencies = plugininfo.dependencies();
-    foreach( QString depName, dependencies )
+    foreach( const QString &depName, dependencies )
         {
         if( !loadEffect(depName))
             {
@@ -866,7 +866,7 @@ void EffectsHandlerImpl::effectsChanged()
     {
     loaded_effects.clear();
 //    kDebug(1212) << "Recreating effects' list:";
-    foreach( EffectPair effect, effect_order )
+    foreach( const EffectPair &effect, effect_order )
         {
 //        kDebug(1212) << effect.first;
         loaded_effects.append( effect );
diff --git a/effects/blur.cpp b/effects/blur.cpp
index 9db4d35298..367c1f792d 100644
--- a/effects/blur.cpp
+++ b/effects/blur.cpp
@@ -303,7 +303,7 @@ void BlurEffect::updateBlurTexture(const QRegion& region)
     QRect bounding = region.boundingRect();
     QVector<QRect> rects = region.rects();
     int totalarea = 0;
-    foreach( QRect r, rects )
+    foreach( const QRect &r, rects )
         totalarea += r.width() * r.height();
     if( (int)(totalarea * 1.33 + 100 ) < bounding.width() * bounding.height() )
         {
@@ -329,7 +329,7 @@ void BlurEffect::updateBlurTexture(const QVector<QRect>& rects)
 
     mSceneTexture->bind();
 
-    foreach( QRect r, rects )
+    foreach( const QRect &r, rects )
         {
         // We change x coordinates here because horizontal blur pass (which
         //  comes after this one) also uses pixels that are horizontally edging
@@ -354,7 +354,7 @@ void BlurEffect::updateBlurTexture(const QVector<QRect>& rects)
 
     mTmpTexture->bind();
 
-    foreach( QRect r, rects )
+    foreach( const QRect &r, rects )
         {
         glBegin(GL_QUADS);
             glVertex2f( r.x()            , r.y() + r.height() );
diff --git a/effects/shadow.cpp b/effects/shadow.cpp
index 6570e36faa..202f4f3a9b 100644
--- a/effects/shadow.cpp
+++ b/effects/shadow.cpp
@@ -112,7 +112,7 @@ void ShadowEffect::drawWindow( EffectWindow* w, int mask, QRegion region, Window
             if( !shadowDatas.isEmpty())
                 d.clip |= shadowDatas.last().clip;
             d.mask = mask;
-            foreach(QRect r, region.rects())
+            foreach(const QRect &r, region.rects())
                 d.region |= shadowRectangle(r);
             d.region &= region;
             shadowDatas.append(d);
diff --git a/effects/taskbarthumbnail.cpp b/effects/taskbarthumbnail.cpp
index 707cc46227..8bcd3adfb1 100644
--- a/effects/taskbarthumbnail.cpp
+++ b/effects/taskbarthumbnail.cpp
@@ -67,7 +67,7 @@ void TaskbarThumbnailEffect::paintWindow( EffectWindow* w, int mask, QRegion reg
     effects->paintWindow( w, mask, region, data ); // paint window first
     if( thumbnails.contains( w ))
         { // paint thumbnails on it
-        foreach( const Data thumb, thumbnails.values( w ))
+        foreach( const Data &thumb, thumbnails.values( w ))
             {
             EffectWindow* thumbw = effects->findWindow( thumb.window );
             if( thumbw == NULL )
diff --git a/effects/test/flame.cpp b/effects/test/flame.cpp
index 797293abed..0322080dcb 100644
--- a/effects/test/flame.cpp
+++ b/effects/test/flame.cpp
@@ -51,7 +51,7 @@ void FlameEffect::paintWindow( EffectWindow* w, int mask, QRegion region, Window
         {
         WindowQuadList new_quads;
         double ylimit = windows[ w ] * w->height(); // parts above this are already away
-        foreach( WindowQuad quad, data.quads )
+        foreach( const WindowQuad &quad, data.quads )
             {
             if( quad.bottom() <= ylimit )
                 continue;
diff --git a/effects/videorecord.cpp b/effects/videorecord.cpp
index 9c88c5cbe3..6db64a236b 100644
--- a/effects/videorecord.cpp
+++ b/effects/videorecord.cpp
@@ -92,7 +92,7 @@ void VideoRecordEffect::postPaintScreen()
         if( CapturyProcessRegionStart( client ) == CAPTURY_SUCCESS )
             {
             capture_region &= QRect( 0, 0, displayWidth(), displayHeight()); // limit to screen
-            foreach( QRect r, capture_region.rects())
+            foreach( const QRect &r, capture_region.rects())
                 {
                 int gly = displayHeight() - r.y() - r.height(); // opengl coords
                 CapturyProcessRegion( client, r.x(), gly, r.width(), r.height());
diff --git a/scene.cpp b/scene.cpp
index a67a7efb11..5c48cdc40e 100644
--- a/scene.cpp
+++ b/scene.cpp
@@ -191,7 +191,7 @@ void Scene::paintGenericScreen( int orig_mask, ScreenPaintData )
         // preparation step
         effects->prePaintWindow( effectWindow( w ), data, time_diff );
 #ifndef NDEBUG
-        foreach( WindowQuad q, data.quads )
+        foreach( const WindowQuad &q, data.quads )
             if( q.isTransformed())
                 kFatal( 1212 ) << "Pre-paint calls are not allowed to transform quads!" ;
 #endif
@@ -200,7 +200,7 @@ void Scene::paintGenericScreen( int orig_mask, ScreenPaintData )
         phase2.append( Phase2Data( w, infiniteRegion(), data.clip, data.mask, data.quads ));
         }
 
-    foreach( Phase2Data d, phase2 )
+    foreach( const Phase2Data &d, phase2 )
         paintWindow( d.window, d.mask, d.region, d.quads );
     }
 
@@ -230,7 +230,7 @@ void Scene::paintSimpleScreen( int orig_mask, QRegion region )
         // preparation step
         effects->prePaintWindow( effectWindow( w ), data, time_diff );
 #ifndef NDEBUG
-        foreach( WindowQuad q, data.quads )
+        foreach( const WindowQuad &q, data.quads )
             if( q.isTransformed())
                 kFatal( 1212 ) << "Pre-paint calls are not allowed to transform quads!" ;
 #endif
@@ -438,7 +438,7 @@ WindowQuadList Scene::Window::buildQuads() const
 WindowQuadList Scene::Window::makeQuads( WindowQuadType type, const QRegion& reg ) const
     {
     WindowQuadList ret;
-    foreach( QRect r, reg.rects())
+    foreach( const QRect &r, reg.rects())
         {
         WindowQuad quad( type );
         // TODO asi mam spatne pravy dolni roh - bud tady, nebo v jinych castech
diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index f0400941c7..92ec98ffd5 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -645,7 +645,7 @@ void SceneOpenGL::flushBuffer( int mask, QRegion damage )
             waitSync();
             if( glXCopySubBuffer )
                 {
-                foreach( QRect r, damage.rects())
+                foreach( const QRect &r, damage.rects())
                     {
                     // convert to OpenGL coordinates
                     int y = displayHeight() - r.y() - r.height();
@@ -658,7 +658,7 @@ void SceneOpenGL::flushBuffer( int mask, QRegion damage )
                 glDrawBuffer( GL_FRONT );
                 int xpos = 0;
                 int ypos = 0;
-                foreach( QRect r, damage.rects())
+                foreach( const QRect &r, damage.rects())
                     {
                     // convert to OpenGL coordinates
                     int y = displayHeight() - r.y() - r.height();
@@ -691,7 +691,7 @@ void SceneOpenGL::flushBuffer( int mask, QRegion damage )
         glXWaitGL();
         waitSync();
         if( mask & PAINT_SCREEN_REGION )
-            foreach( QRect r, damage.rects())
+            foreach( const QRect &r, damage.rects())
                 XCopyArea( display(), buffer, rootWindow(), gcroot, r.x(), r.y(), r.width(), r.height(), r.x(), r.y());
         else
             XCopyArea( display(), buffer, rootWindow(), gcroot, 0, 0, displayWidth(), displayHeight(), 0, 0 );
@@ -877,7 +877,7 @@ QRegion SceneOpenGL::Texture::optimizeBindDamage( const QRegion& reg, int limit
     // between all the areas and the bounding rectangle is small, simply use
     // only the bounding rectangle
     int size = 0;
-    foreach( QRect r, reg.rects())
+    foreach( const QRect &r, reg.rects())
         size += r.width() * r.height();
     if( reg.boundingRect().width() * reg.boundingRect().height() - size < limit )
         return reg.boundingRect();
@@ -983,7 +983,7 @@ bool SceneOpenGL::Texture::load( const Pixmap& pix, const QSize& size,
                 mSize.width(), mSize.height(), depth );
             QRegion damage = optimizeBindDamage( region, 100 * 100 );
             glPixelStorei( GL_UNPACK_ROW_LENGTH, mSize.width());
-            foreach( QRect r, damage.rects())
+            foreach( const QRect &r, damage.rects())
                 { // TODO for small areas it might be faster to not use SHM to avoid the XSync()
                 XCopyArea( display(), pix, p, gc, r.x(), r.y(), r.width(), r.height(), 0, 0 );
                 glXWaitX();
@@ -1030,7 +1030,7 @@ bool SceneOpenGL::Texture::load( const Pixmap& pix, const QSize& size,
             {
             glBindTexture( mTarget, mTexture );
             QRegion damage = optimizeBindDamage( region, 30 * 30 );
-            foreach( QRect r, damage.rects())
+            foreach( const QRect &r, damage.rects())
                 {
                 // convert to OpenGL coordinates (this is mapping
                 // the pixmap to a texture, this is not affected
diff --git a/scene_xrender.cpp b/scene_xrender.cpp
index 7432a75958..fb116cdcda 100644
--- a/scene_xrender.cpp
+++ b/scene_xrender.cpp
@@ -222,7 +222,7 @@ void SceneXrender::paintTransformedScreen( int orig_mask )
         // preparation step
         effects->prePaintWindow( effectWindow( w ), data, time_diff );
 #ifndef NDEBUG
-        foreach( WindowQuad q, data.quads )
+        foreach( const WindowQuad &q, data.quads )
             if( q.isTransformed())
                 kFatal( 1212 ) << "Pre-paint calls are not allowed to transform quads!" ;
 #endif
@@ -254,7 +254,7 @@ void SceneXrender::paintTransformedScreen( int orig_mask )
     // That we draw bottom to top is important now since we're drawing translucent objects
     // and also are clipping only by opaque windows.
     QRegion add_paint;
-    foreach( Phase2Data d, phase2 )
+    foreach( const Phase2Data &d, phase2 )
         {
         Scene::Window* w = d.window;
         paintWindow( w, d.mask, d.region | add_paint, d.quads );