[Qt-interest] Model/View speed of Models with many many items and item changes

[RZ]

> The problem is probably that the standard models send a dataChanged() for each 
> changed index.

I can strengthen that; doing

myModel->blockSignals(true);
// manipulate lots of data
myModel->blockSignals(false);

improved speed about a factor of 100. I don't know why - but it worked ;-)