code: function rememberSelectedChildren(oNode, oRootNode) {
  		var aNodes = oNode._getNodes(),
  			oCurrentNode;
  
  		for (var i = 0; i < aNodes.length; i++) {
  			oCurrentNode = aNodes[i];
  
  			if (oCurrentNode.getIsSelected()) {
  				oRootNode.addAssociation("selectedForNodes", oCurrentNode, true);
  			}
  
  			rememberSelectedChildren(oCurrentNode, oRootNode);
  		}
  	}
docs: Adds references inside the collapsed node of all its selected children recursively.
  @param {sap.ui.commons.TreeNode} oNode The current node to look at
  @param {sap.ui.commons.TreeNode} oRootNode The root node that was collapsed