fix crash in QWidgetPrivate::screenGeometry

Missing null check added. Not really a Windows CE only crash.
The following code crashed on all platforms, because the
QGraphicsProxyWidget had no scene yet.

QPushButton *button = new QPushButton;
QGraphicsProxyWidget *buttonProxy = new QGraphicsProxyWidget;
buttonProxy->setWidget(button);
qApp->desktop()->screenGeometry(button);

Task-number: QTBUG-5626
Reviewed-by: Alessandro Portale

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gui/kernel/qwidget_p.h b/src/gui/kernel/qwidget_p.h
index df28bac..eea929b 100644
--- a/src/gui/kernel/qwidget_p.h
+++ b/src/gui/kernel/qwidget_p.h
@@ -479,7 +479,7 @@ public:
         QGraphicsProxyWidget *ancestorProxy = widget->d_func()->nearestGraphicsProxyWidget(widget);
         //It's embedded if it has an ancestor
         if (ancestorProxy) {
-            if (!bypassGraphicsProxyWidget(widget)) {
+            if (!bypassGraphicsProxyWidget(widget) && ancestorProxy->scene() != 0) {
                 // One view, let be smart and return the viewport rect then the popup is aligned
                 if (ancestorProxy->scene()->views().size() == 1) {
                     QGraphicsView *view = ancestorProxy->scene()->views().at(0);