Layout cell with .attachObject does not inherit skin

I’ve created a 2U layout object. The right hand side has a grid and all looks good there but I do an attachObject on the left attaching a DIV and it’s background is white or perhaps more accurately unspecified. How can I change the background color of my left hand side bar?
thanks,
Jim Dixon

CSS of layout cell background is the next:

table.dhtmlxLayoutPolyContainer_dhx_blue td.dhtmlxLayoutSinglePoly div.dhxcont_global_content_area { background-color: #FFFFFF; }
If you need to set bg only for cell A - try the next;

layout.cells("a").firstChild.childNodes[1].style.backgroundColor = "#00CED1";