Google Chrome - auto scrollbars not working as expected? -

google chrome - horizontal overflow works expected, but, vertical overflow causing showing bottom scrollbar too?

code on: http://jsfiddle.net/5yflgo16/ 

what want? using js center div on page. want browser show vertical or horizontal scrollbar, or both scrollbars when needed. in mentioned example, can see browser showing both of scrollbars when comes vertical overflow. max-width , max-height set 100 px, but, browser shows horizontal scrollbar if width of div not 100px. showing scrollbar on 50px wide div, ability scroll 8 px... 58px, still less maximal 100px. works if force 100px width, or if div not fixed. div have fixed, @ middle of page, , have max 100 x 100 px. user "gmo" convincing me wrong expectations problem. how comes there no problem when overflow horizontal (bottom left example), , show needed, bottom scrollbar, , when comes vertical overflow, browser show both bottom , side scrollbar (top right).