Canvas Mouse Positioning Incorrect in IE10

Canvas Mouse Positioning Incorrect in IE10

I am having an issue with Internet Explorer 10 not properly registering
the location of the mouse on the <canvas> element if it is not up against
the top of the page. Open up IE10 and look at the links below.



The problem:
Click on this link and try dragging the nodes of the graph around:
http://ffi-server.no-ip.biz:257/test/good.html
Now, try the same thing on this page:
http://ffi-server.no-ip.biz:257/test/bad.html
Interestingly, IE9 does not have this issue, and adding a <meta> tag to
tell IE10 to render the page as IE9 does not solve this issue.



Possible solution?
I think I have found the problematic line of code, I just can't figure out
how to correct it. Look at line 3044 in: http://pastebin.com/82GJBiEB
I just don't know how to correct it. I believe that IE10 is reporting a
different e.pageY value than browsers which are working correctly. You can
verify that by clicking on different areas of the canvas on this page:
http://ffi-server.no-ip.biz:257/test/alert.html and see the reported
values in IE10 and, say. Chrome.



Could anyone suggest a way to correct this issue?
Thank you for your time!