Index: plasma/containments/panel/panel.h
===================================================================
--- plasma/containments/panel/panel.h	(Revision 940781)
+++ plasma/containments/panel/panel.h	(Arbeitskopie)
@@ -54,6 +54,9 @@
 protected:
     void saveState(KConfigGroup &config) const;

+  public slots:
+    void setBlendInterface(bool);
+
 private slots:
     void themeUpdated();
     void backgroundChanged();
@@ -83,6 +86,7 @@
     bool m_maskDirty;
     int m_spacerIndex;
     Spacer *m_spacer;
+    bool m_blendInterface;

     friend class Spacer;
 };
Index: plasma/containments/panel/panel.cpp
===================================================================
--- plasma/containments/panel/panel.cpp	(Revision 940781)
+++ plasma/containments/panel/panel.cpp	(Arbeitskopie)
@@ -93,7 +93,8 @@
       m_currentSize(QSize(Kephal::ScreenUtils::screenSize(screen()).width(), 35)),
       m_maskDirty(true),
       m_spacerIndex(-1),
-      m_spacer(0)
+      m_spacer(0),
+      m_blendInterface(false)
 {
     m_background = new Plasma::FrameSvg(this);
     m_background->setImagePath("widgets/panel-background");
@@ -495,6 +496,10 @@
     }
 }

+void Panel::setBlendInterface(bool blend) {
+    m_blendInterface = blend;
+}
+
 void Panel::saveState(KConfigGroup &config) const
 {
     config.writeEntry("minimumSize", minimumSize());
@@ -564,8 +569,8 @@
         }
     }

-    // blit the background (saves all the per-pixel-products that blending does)
-    painter->setCompositionMode(QPainter::CompositionMode_Source);
+    // blit the background (saves all per-pixel-products that blending does)
+    painter->setCompositionMode(m_blendInterface ? QPainter::CompositionMode_SourceOver : QPainter::CompositionMode_Source);
     painter->setRenderHint(QPainter::Antialiasing);

     m_background->paintFrame(painter, option->exposedRect);
Index: plasma/shells/desktop/desktopview.h
===================================================================
--- plasma/shells/desktop/desktopview.h	(Revision 940781)
+++ plasma/shells/desktop/desktopview.h	(Arbeitskopie)
@@ -82,6 +82,7 @@
     void setContainment(Plasma::Containment *containment);

 protected:
+    void paintEvent(QPaintEvent* event);
     void wheelEvent(QWheelEvent *event);
     void drawBackground(QPainter *painter, const QRectF &rect);

Index: plasma/shells/desktop/desktopview.cpp
===================================================================
--- plasma/shells/desktop/desktopview.cpp	(Revision 940781)
+++ plasma/shells/desktop/desktopview.cpp	(Arbeitskopie)
@@ -42,6 +42,7 @@
 #include "dashboardview.h"
 #include "plasmaapp.h"
 #include "plasma-shell-desktop.h"
+#include "panelview.h"

 #ifdef Q_WS_WIN
 #include "windows.h"
@@ -263,6 +264,15 @@
     }
 }

+void DesktopView::paintEvent(QPaintEvent* event) {
+    foreach(PanelView* view, PlasmaApp::self()->panelViews()) {
+        QRect intersection = view->geometry() & QRect(mapToGlobal(event->rect().topLeft()), mapToGlobal(event->rect().bottomRight()));
+        if(!intersection.isEmpty())
+            view->undergroundChanged(QRect(view->mapFromGlobal(intersection.topLeft()), view->mapFromGlobal(intersection.bottomRight())));
+    }
+    QGraphicsView::paintEvent(event);
+}
+
 void DesktopView::wheelEvent(QWheelEvent* event)
 {
     QGraphicsItem * item = scene() ? scene()->itemAt(sceneRect().topLeft() + event->pos()) : 0;
Index: plasma/shells/desktop/panelview.h
===================================================================
--- plasma/shells/desktop/panelview.h	(Revision 940781)
+++ plasma/shells/desktop/panelview.h	(Arbeitskopie)
@@ -177,6 +177,11 @@
      */
     void recreateUnhideTrigger();

+    /**
+     * Notification that the undergound of this panel-view has changed
+     */
+    void undergroundChanged(QRect area);
+
 protected Q_SLOTS:
     void updateStruts();

Index: plasma/shells/desktop/panelview.cpp
===================================================================
--- plasma/shells/desktop/panelview.cpp	(Revision 940781)
+++ plasma/shells/desktop/panelview.cpp	(Arbeitskopie)
@@ -44,6 +44,7 @@
 #include "plasmaapp.h"

 #include <kephal/screens.h>
+#include "desktopview.h"

 class GlowBar : public QWidget
 {
@@ -1197,13 +1198,43 @@
     Plasma::View::leaveEvent(event);
 }

-void PanelView::drawBackground(QPainter *painter, const QRectF &rect)
-{
-    if (PlasmaApp::hasComposite()) {
-        painter->setCompositionMode(QPainter::CompositionMode_Source);
-        painter->fillRect(rect.toAlignedRect(), Qt::transparent);
-    } else {
-        Plasma::View::drawBackground(painter, rect);
+bool useDesktopTransparency = true;
+
+void PanelView::undergroundChanged(QRect area) {
+    if(!PlasmaApp::hasComposite() && useDesktopTransparency)
+        update(area);
+}
+
+void PanelView::drawBackground(QPainter *painter, const QRectF &_rect)
+{
+      QRectF rect(_rect);
+      DesktopView* desktopView = PlasmaApp::self()->viewForPanel(this);
+      if(containment())
+          QMetaObject::invokeMethod(containment(), "setBlendInterface", Q_ARG(bool, false));
+
+      if (PlasmaApp::hasComposite()) {
+          painter->setCompositionMode(QPainter::CompositionMode_Source);
+          painter->fillRect(rect.toAlignedRect(), Qt::transparent);
+      } else if(desktopView && useDesktopTransparency) {
+          painter->setCompositionMode(QPainter::CompositionMode_Source);
+
+          //Map 'rect' from the panel into the desktop view
+          QRectF desktopRect = mapFromScene(rect).boundingRect();
+          desktopRect.translate(pos().x(), pos().y());
+          desktopRect.translate(-desktopView->pos().x(), -desktopView->pos().y());
+          QRect grab = desktopRect.toRect();
+          grab &= QRect(QPoint(0, 0), desktopView->size()); //Sometimes the scene-mapping maps one pixel too far outside, so restrict the area
+
+          useDesktopTransparency = false; //Disable desktop transparency temporarily to prevent endless updating from within undergoundChanged
+          QPixmap grabbed = QPixmap::grabWidget(desktopView, grab);
+          useDesktopTransparency = true;
+
+          painter->drawPixmap(rect, grabbed, QRectF(0, 0, grab.width(), grab.height()));
+
+      if(containment()) //Tell the panel to blend the interface over the background, so it isn't discarded
+          QMetaObject::invokeMethod(containment(), "setBlendInterface", Q_ARG(bool, true));
+      }else{
+          Plasma::View::drawBackground(painter, rect);
     }
 }

Index: plasma/shells/desktop/plasmaapp.h
===================================================================
--- plasma/shells/desktop/plasmaapp.h	(Revision 940781)
+++ plasma/shells/desktop/plasmaapp.h	(Arbeitskopie)
@@ -80,6 +80,11 @@
      */
     QList<PanelView*> panelViews() const;

+    /**
+     * Returns the currently active desktop that this panel is visible on, or zero
+     */
+    DesktopView* viewForPanel(PanelView* panel) const;
+
     static bool isPanelContainment(Plasma::Containment *containment);

 #ifdef Q_WS_X11
Index: plasma/shells/desktop/plasmaapp.cpp
===================================================================
--- plasma/shells/desktop/plasmaapp.cpp	(Revision 940781)
+++ plasma/shells/desktop/plasmaapp.cpp	(Arbeitskopie)
@@ -446,6 +446,21 @@
     }
 }

+DesktopView* PlasmaApp::viewForPanel(PanelView* panel) const {
+
+    int currentDesktop = -1;
+    if (AppSettings::perVirtualDesktopViews())
+        currentDesktop = KWindowSystem::currentDesktop()-1;
+
+
+    foreach (DesktopView *view, m_desktops)
+        if((view->desktop() == currentDesktop || currentDesktop == -1) && !(view->geometry() & panel->geometry()).isEmpty())
+            if(!view->isHidden())
+                return view;
+
+    return 0;
+}
+
 DesktopView* PlasmaApp::viewForScreen(int screen, int desktop) const
 {
     foreach (DesktopView *view, m_desktops) {