rem: this.scrollToRow(line - total / 2); 
add: this.scrollToRow(line - (last - first + 1) / 2); 
context: function bov_ctrln (line){    var first = this.tree.getFirstVisibleRow();    var last = this.tree.getLastVisibleRow();    this.scrollToRow(line - total / 2);}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/6b7c961af3c8d8c73aa3b01e4b413f4b31418399/tree-utils.js/clean/extensions/venkman/resources/content/tree-utils.js