I'd say it's a misdesign on your side. Do you really need 80000 editors open at the same time? You won't modify all the items at once, will you? I modified your code, as I'm not patient enough to wait an hour before the application starts up, so that it only opened 5000 editors and it still behaved awfully. Each time I scrolled something, all the widgets needed to be repositioned - first they disappeared from the view and then I turned off the application before they had a chance to show up again (again, I'm not patient enough). You should really reconsider changing your design. The easiest way would be to only use editors for a single row and for all the other rows just paint the same set of controls a spinbox has so that it can mimic its look. I'm sure it'll get a looooooot faster this way.