side bar on lelf

Hi,
Thank you for your very nice theme.
I have a very small issue.
When I put the sidebar on the right side, everything is OK, I get a nice shading on the side.
When the sidebar is on the left side, I get a kind of scroll bar (without handles) which is not very nice. How can I avoid it.
I reproduce it on chrome, IE and firefox.
I gor a picture of the screen but don’t know haw to provide it as an example.
DéHème
sorry for my frenglish