rem: if ("_treeView" in this && "tree" in this._treeView) 
add: if ("_treeView" in this && "tree" in this._treeView && this._treeView.tree) 
context: function torr_vfpchange (start, amount){    if (!this._treeView.frozen)    {        this.invalidateCache();        this.visualFootprint += amount;        if ("_treeView" in this && "tree" in this._treeView)        {            if (amount != 0)                this._treeView.tree.rowCountChanged (start, amount);            else                this._treeView.tree.invalidateRow (start);        }    }    else    {        if ("changeAmount"  in this._treeView)            this._treeView.changeAmount += amount;        else            this._treeView.changeAmount = amount;        if ("changeStart" in this._treeView)            this._treeView.changeStart =                 Math.min (start, this._treeView.changeStart);        else            this._treeView.changeStart = start;    }}
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/92b1e3b67c6c3ef1915d2a0e18c1fa7be21e200e/tree-utils.js/buggy/extensions/venkman/resources/content/tree-utils.js