System.Windows.Forms.TreeView._SelectPrevious C# (CSharp) Method

        private bool _SelectPrevious(int fromIndex)
        {
            if (fromIndex - 1 >= 0)
            {
                if (_nodeList[fromIndex - 1].Enabled == false) return false;

                SelectedNode = _nodeList[fromIndex - 1];
                _AddjustScrollIndexToSelectedNode();
                SelectedNodeChanged(this, new TreeViewEventArgs(SelectedNode));
                return true;
            }

            return true;
        }
        private void TreeView_Resize(object sender, EventArgs e)