We compress multiple proxyModelStructureChanged() emitted during loading charts now into one single call at the end of the loading process what gives us a huge speed-up when loading charts.
With my test-document ( Harmattan-Columbus_SW_Maturity_Applications_Release-W19_10.xls ) loading all the charts in that Excel document is done more then double as fast now (before ~40-50ms per chart and after this patch ~10-20ms).