code: function() {
       var paddingLeft = 0;
       if (this.g.vis.get("labels")) { paddingLeft += this.getLabelWidth(); }
       if (this.g.vis.get("metacell")) { paddingLeft += this.getMetaWidth(); }
       //paddingLeft += 15 # scroll bar
       return paddingLeft;
    }
docs: length of all elements left to the main sequence body: labels, metacell, ..