Run the preQuery() on all active handlers.
protected function _preQuery() {
foreach ($this::viewsHandlerTypes() as $key => $info) {
$handlers =& $this->{$key};
$position = 0;
foreach ($handlers as $id => $handler) {
$handlers[$id]->position = $position;
$handlers[$id]
->preQuery();
$position++;
}
}
}