QDesktopWidget::resized does not support xrandr 1.2 or newer

QDesktopWidget::resized is not aware of xinerama.

qt-x11-opensource-src-4.4.0/src/gui/kernel/qapplication_x11.cpp
// update the size for desktop widget
int scr = XRRRootToScreen(X11->display, event->xany.window);
+ printf("Desktop resized | screen %d\n",scr);
QWidget *w = desktop()->screen(scr);
QSize oldSize(w->size());
w->data->crect.setWidth(DisplayWidth(X11->display, scr));

the problem stems from the fact that XRRRootToScreen() returns the X11 screen when in fact the code expects it to return the xinerama screen which is quite different.