Piechart percentages not displaying in IE9

The percentages in the pie chart should display when you hover over a segment. This does not work in IE9. The problem is not positioning, since explicitly selecting the segment using left click/F5 does display the percentage.

Forcing the browser into standards mode does not help.

Start by reproducing the pie-chart hover behavior in IE9 and compare it with explicitly selecting a segment using left click/F5, which does display the percentage. Done means percentages appear when hovering over every pie-chart segment in IE9 without relying on standards mode.

Written by the indexing model from the issue text.