Check for null pointer in QGraphicsProxyWidget::event() in case there is no focusWidget().
Check for null pointer in QGraphicsProxyWidget::event() in case there is no focusWidget().

Reviewed-by: Thierry
Task-number: 255468

igor-sfdc/qt-wk,igor-sfdc/qt-wk,RLovelett/qt,RLovelett/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,RLovelett/qt,pruiz/wkhtmltopdf-qt,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,KDE/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,radekp/qt,KDE/qt,KDE/qt,radekp/qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,igor-sfdc/qt-wk,RLovelett/qt,radekp/qt,KDE/qt,pruiz/wkhtmltopdf-qt,KDE/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,RLovelett/qt,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,KDE/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,KDE/qt,KDE/qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,igor-sfdc/qt-wk,RLovelett/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk