I use qcustomplot to show real-time data. As amount of data grows, load of CPU for replotting increases. Because it has to replot whole graph. So I want to define another two QCPLayer. When time is beyond 5000s, I use the first QCPLayer defined by myself to replot separately through setlayer(QCPLayer::lmbuffered) so that the former data needn't be painted redundantly.I use second QCPLayer to show data when beyond 10000s. But the two layers don't show data. It is a little bit strange.