function mxCurrentRootChange(a,b){this.view=a;this.previous=this.root=b;this.isUp=null==b;if(!this.isUp){a=this.view.currentRoot;for(var c=this.view.graph.getModel();null!=a;){if(a==b){this.isUp=!0;break}a=c.getParent(a)}}}