Native controls also responded better. The new web-based pop-ups can take a long while to render if a heavy page is being loaded. So if I try to quit Firefox,

Native controls also responded better. The new web-based pop-ups can take a long while to render if a heavy page is being loaded. So if I try to quit Firefox, the "are you sure you want to quit" popup renders empty until the current page is done. Sure, this happens only on high resource usage, but the previous implementation di not suffer from this.