Well for me usability includes reasonable contrasts so you can distinguish the bar/train in the scrollbar from the scroll-track/rail.
If it looks like a soup with poor contrast, then its difficult to distinguish, and then it has poor usability, I think.
Well for me usability includes reasonable contrasts so you can distinguish the bar/train in the scrollbar from the scroll-track/rail.
If it looks like a soup with poor contrast, then its difficult to distinguish, and then it has poor usability, I think.