Doesnt works autohide featur for task bar in windows xp

hi kevin
I have been using it for a while and m quite glad with the outlay and features..i have one major issue with it, that is it doesn't allows the taskbar to be shown when maximised, though i have set the taskbar to be on top of all windows with autohide feature enabled. I have to minimize it and then switch to other windows.
thanks & regards
gaurav gupta