Replaced some calls to repaint() with ones to update() since the former may result recursion in some cases (not that it has ever happened to us, but we never know how we might end up using some of our widgets in the future). Otherwise, regarding the progress bar widget, I couldn't see any choppy progress on Windows. So, it might be that Qt improved things in that respect? Same with the file organiser widget: we don't need to update the widget after trying to drop the same file again.