Index: widget.cpp
===================================================================
--- widget.cpp  (revision 722701)
+++ widget.cpp  (working copy)
@@ -325,6 +325,7 @@
         // Recreate the pixmap if it's gone.
         if (pix.isNull()) {
             pix = QPixmap(d->cacheSize);
+            pix.fill(Qt::transparent);
             exposed = brect;
         }

@@ -336,17 +337,11 @@
             cacheOption.exposedRect = exposed.toRect(); // <- truncation

             QPainter pixmapPainter(&pix);
-
             // Fit the item's bounding rect into the pixmap's coordinates.
             pixmapPainter.scale(pix.width() / brect.width(),
-                                pix.height() / brect.height());
+                    pix.height() / brect.height());
             pixmapPainter.translate(-brect.topLeft());

-            // erase the exposed area so we don't paint over and over
-            pixmapPainter.setCompositionMode(QPainter::CompositionMode_Source);
-            pixmapPainter.fillRect(exposed, Qt::transparent);
-            pixmapPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
-
             // Re-render the invalidated areas of the pixmap. Important: don't
             // fool the item into using the widget - pass 0 instead of \a
             // widget.
@@ -372,6 +367,7 @@
         // Auto-adjust the pixmap size.
         if (deviceRect.size() != pix.size()) {
             pix = QPixmap(deviceRect.size());
+            pix.fill(Qt::transparent);
             exposed = brect;
         }

@@ -388,16 +384,9 @@

             // Transform the painter, and render the item in device coordinates.
             QPainter pixmapPainter(&pix);
-
             pixmapPainter.translate(offset);
             pixmapPainter.setWorldTransform(transform, true);
             pixmapPainter.translate(transform.inverted().map(QPointF(0, 0)));
-
-            // erase the exposed area so we don't paint over and over
-            pixmapPainter.setCompositionMode(QPainter::CompositionMode_Source);
-            pixmapPainter.fillRect(exposed, Qt::transparent);
-            pixmapPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
-
             paintWidget(&pixmapPainter, &cacheOption, 0);
             pixmapPainter.end();