FYI:

Everything works fine with following modifications I've made:
=================================
#else
QObjectList *children = (QObjectList *)w->children();
if ( children )
{
for ( QObjectListIterator it(*children); it.current(); ++it )
{
QObject *obj = (QObject *)it.current();
if ( obj->inherits("QwtPicker") )
{
QwtPicker *picker = (QwtPicker *)obj;
if ( picker->isEnabled() )
{
pickers.resize(pickers.size() + 1);
pickers[(int)pickers.size() - 1] = picker; //!!!!! HERE
// pickers[pickers.size() - 1] = picker;
}
}
}
}
#endif
===============================

Thanks!