code: function mxCurrentRootChange(view, root)
  {
  	this.view = view;
  	this.root = root;
  	this.previous = root;
  	this.isUp = root == null;
  	
  	if (!this.isUp)
  	{
  		var tmp = this.view.currentRoot;
  		var model = this.view.graph.getModel();
  		
  		while (tmp != null)
  		{
  			if (tmp == root)
  			{
  				this.isUp = true;
  				break;
  			}
  			
  			tmp = model.getParent(tmp);
  		}
  	}
  }
docs: Class: mxCurrentRootChange
  
  Action to change the current root in a view.
  
  Constructor: mxCurrentRootChange
  
  Constructs a change of the current root in the given view.