My English is not my forte, i'm sorry give you the inconvenience of reading.
I am sorry for the inconveniences I caused you due to my English inadequacy. The bug's main effects is when the table of contents is too large, switching the mouse cursor between the table of contents and the main content will cause the page width to constantly decrease. However, when the page width has decreased to its minimum, the view will return to normal. It will then decrease again, and continue the cycle.
To show the bug, I have put my page on http://www.jspwiki.org. The specific web address is http://www.jspwiki.org/wiki/%E9%9B%BE%E5%86%89.
I discovered a problem. The bug will only show in the IE9 browser, and it's only when compatibility view mode is not enabled!
Thank you for w34p0nx's help me to translate this description!