I'm aware that unity uses yet another scrollbar than the ayatana-scrollbars and the GTK ones, but the ayatana ones are not rounded; why should the unity one be?
Anyway, this is an UI detail which does not affect strings or breaks the meaning of screenshots, so this doesn't sound like a problem. But please consider at least some consistency in the scrollbars.
I'm aware that unity uses yet another scrollbar than the ayatana-scrollbars and the GTK ones, but the ayatana ones are not rounded; why should the unity one be?
Anyway, this is an UI detail which does not affect strings or breaks the meaning of screenshots, so this doesn't sound like a problem. But please consider at least some consistency in the scrollbars.