Fix KRootBacking failure when no window is displayed

This partially resolves Bug 811
(cherry picked from commit 2771be6210)

kdeui/krootpixmap.cpp

@@ -234,8 +234,9 @@ void KRootPixmap::repaint(bool force)
     m_Rect = TQRect(p1, p2);
 #ifdef Q_WS_X11
     m_Desk = KWin::windowInfo(m_pWidget->topLevelWidget()->winId()).desktop();
-    if (m_Desk == NET::OnAllDesktops)
+    if ((m_Desk == NET::OnAllDesktops) || (m_Desk == 0)) {
 	m_Desk = currentDesktop();
+    }
 
     // KSharedPixmap will correctly generate a tile for us.
     m_pPixmap->loadFromShared(pixmapName(m_Desk), m_Rect);

libkscreensaver/kscreensaver.cpp

@@ -47,6 +47,8 @@ KScreenSaver::KScreenSaver( WId id ) : TQWidget()
     unsigned int w = 0;
     unsigned int h = 0;
 
+    XSync(qt_xdisplay(), false);
+
     d = new KScreenSaverPrivate;
     d->owner = TQT_TQWIDGET(find( id ));
     if ( d->owner )