By reimplementing setData() in the proxy model, I managed to get changes in the proxy model to be reflected by in the original model.

However, I am still having a slight problem keeping the proxy in sync with the original model. For example, if I changed row 1, column 1, from "1" (the original value) to "A", the proxy model's view is not updated until I do something like move the scroll bar or something else that generates events or signals.

Which signal should I connect to which slot (and which object)?