code: function _getElementTreeLeftColumnOfListItem(controls, paddingLeft) {
  			var html = "<offset style=\"padding-left:" + paddingLeft + "px\" >";
  
  			if (controls.content.length > 0) {
  				html += "<arrow down=\"true\"></arrow>";
  			} else {
  				html += "<place-holder></place-holder>";
  			}
  
  			html += "</offset>";
  
  			return html;
  		}
docs: Create HTML for the left part of the ElementTree list item.
  @param {ElementTreeOptions.controls} controls
  @param {number} paddingLeft
  @returns {string}
  @private