mxGraphModel.prototype.rootChanged=function(a){var b=this.root;this.root=a;this.nextId=0;this.cells=null;this.cellAdded(a);return b};mxGraphModel.prototype.isRoot=function(a){return null!=a&&this.root==a};mxGraphModel.prototype.isLayer=function(a){return this.isRoot(this.getParent(a))};mxGraphModel.prototype.isAncestor=function(a,b){for(;null!=b&&b!=a;)b=this.getParent(b);return b==a};mxGraphModel.prototype.contains=function(a){return this.isAncestor(this.root,a)};