markTimespan greying out every day in day view

Hi. I’ve implemented markTimespan on a scheduler.

scheduler.markTimespan({ days: 3, zones: [7*60,8*60,10*60,15*60], invert_zones: true, css: "gray_section", type: "dhx_time_block" //the hardcoded value });
However when I enter day view and view a Wednesay the times are not greyed. I tried using

scheduler.attachEvent("onViewChange", function (new_mode , new_date){ alert(new_date); scheduler.markTimespan({ days: 3, zones: [4*60,8*60,12*60,15*60], invert_zones: true, css: "gray_section", type: "dhx_time_block" //the hardcoded value }); });
but this is greying out the times on every day(Monday to Sunday) I view in the day view(not just Wednesday). Is there an easy implemtation for this or will I have to test the day that is being displayed?

Thanks in advance