Fixed Position - Layouts - Scrolling

Hi, I have a mainlayout which contains left,mid,right layouts. I want left and right layouts stay same and mid layouts going up while scrolling down. I fixed the positions of left and right layouts with css(position:fixed) and it works as I wanted. The problem is when I click restore down(minimize) button of browser, when I scroll to left or right these left and right layouts stays fixed since their position fixed. Is there a solution for this? Can I fix their position for only y axis? Thanks in advance.