diff --git a/IPython/frontend/html/notebook/static/js/tooltip.js b/IPython/frontend/html/notebook/static/js/tooltip.js
index 76c8675..8d07cbf 100644
--- a/IPython/frontend/html/notebook/static/js/tooltip.js
+++ b/IPython/frontend/html/notebook/static/js/tooltip.js
@@ -293,9 +293,9 @@ var IPython = (function (IPython) {
var anchor = this.code_mirror.cursorCoords(false);
var head = this.code_mirror.cursorCoords(true);
var pos = {};
- pos.y = head.y
- pos.yBot = head.yBot
- pos.x = (head.x+anchor.x)/2;
+ pos.y = head.top
+ pos.yBot = head.bottom
+ pos.x = (head.left+anchor.left)/2;
var xinit = pos.x;
var xinter = o.left + (xinit - o.left) / w * (w - 450);