Going to livedemo scrollable sample I can't reproduce this using steps you described. IE7 FF3
And I can't found such issue opened(around for ages). So if you can provide sample for concrete case where scripts hangs - just open issue.
Hi folks, only for testing purpose I have also tried to reproduce this bug.
With FF3 I wasn't able to produce it.
But with IE 6.0.2900.5512.xpsp_sp3_gdr.080814-1236 I got also the same JS Pop. First the selection wasn't done correctly (a lot of blue marked areas in the IE), than the IE works multiple minutes and then I got the JS Message.
I get the same thing with IE7 (7.0.5730.13) and with FF3 (3.0.5).
To reproduce, after selecting all the rows, try to do something else on the page (e.g., move the scroller in the table).
A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.