Weird IE behavior - Test page

I've written a complex jQuery table plugin for an intranet application wich supports different selection models (single, multiple, exclusive), nested expandable hierarchical tables (like a tree) etc. Everything works well, but now while the application goes tested by some clients I stumbled by an very ugly performance issue in IE. The problem appers only on IE machines. FF and Mozilla is fine. For an easier problem tracking I've extracted the problematic code from the plugin and provide a simple test example. Please follow the next steps and try to retrace the problem.

• Load the the test page with one of the following links in your browser
• Try moving the mouse (quick) over the table and watch the performance (highlight row follows mouse) and the mouse pointer (usually a pointer)
• Now click somewhere in the page - doesn't matter if on the table or on the body background
• Try moving the mouse over the table again and watch the performance and the mouse pointer now. The highligtning is now very bumpy und the mouse pointer toggles between a hour glass and the pointer.
• Try the test page w/o logging
• Try the test page with logging

There is no event registration by my plugin on the page nether on the background. What happens after clicking on the page? What is the reason for the slow down of the browser? Is it a jQuery problem or a browser problem?
My config Thinkpad T60,Windows XP SP2, IE6.0.2900.2180.xpsp.050928-1517.

Thanks for any hint @ devsteff@gmx.de