diff -rupN 3/orig/qwidget.cpp 3/new/qwidget.cpp
--- 3/orig/qwidget.cpp	Thu Dec  8 07:06:02 2011
+++ 3/new/qwidget.cpp	Thu Jan 19 09:42:09 2012
@@ -8659,14 +8659,16 @@ bool QWidget::event(QEvent *event)
 
     case QEvent::WindowBlocked:
     case QEvent::WindowUnblocked:
-        {
+        if(isVisible()) {
             QList<QObject*> childList = d->children;
             for (int i = 0; i < childList.size(); ++i) {
                 QObject *o = childList.at(i);
                 if (o && o != QApplication::activeModalWidget()) {
-                    if (qobject_cast<QWidget *>(o) && static_cast<QWidget *>(o)->isWindow()) {
+                    QWidget* ow = qobject_cast<QWidget *>(o);
+                    if(ow && (!ow->isVisible() || ow->isWindow())){
                         // do not forward the event to child windows,
-                        // QApplication does this for us
+                        // QApplication does this for us.
+                        // also, don't forward to hidden children
                         continue;
                     }
                     QApplication::sendEvent(o, event);