Dhtmlxlayout initial size with autosize

If I specify an initial size, autosize doesn’t seem to be done anymore. How do I tell the dhtmlxlayout to start with a size of 275 pixel for the right pane. But autosize both right and left if the layout size changes?

var layout_data = { parent: "layout", pattern: "2U", activeSkin: "dhx-black", cells: [{id: "a", width="275"}, {id: "b"}, ] }; layout = new dhtmlXLayoutObject(layout_data); layout.cells("a").attachObject("navigation"); layout.cells("b").attachObject("doc"); layout.setAutoSize("a;b", "a;b");

Any information?

Do the next changes:
cells: [{id: “a”, width: “275”}, {id: “b”}]

OK.