(In reply to Josef Reidinger from comment #4) > thanks, for logs and way to reproduce it. I reproduce it locally. From logs > I see that problem is not solver, so it is problem with too many packages in > UI, which need time to render. > > Reason why second case is facter is that only few packages are listed, so it > operates faster, but e.g. in my case the first case shows around 53 000 > packages, which slows down UI. And since Yast2 is using Qt, the only way this is slow is if you are using Qt wrong. Qt Model/View framework can very easily scale to millions of rows and be just as efficient as displaying 100 items. The only problem is using convenience classes that use QWidget based classes inside containers. Using 50,000+ QWidget based items will slow things down but I didn't look if this is what Yast2 is doing.