I had the same problem but it was because the javascript file was still in the browser cache of the user even if I upgraded the server libraries to RC4.
Jeremy Thomerson-5 wrote:
Is anyone still having issues with modal windows and IE8 even after
WICKET-2207 [1] was fixed (rc4)? I have one application that uses
several modal windows, and the customer is reporting that it is broken
in IE8 - even after I upgraded them to rc4.
I need to get a machine locally that has IE8 - just haven't had the chance yet.
[1] -
https://issues.apache.org/jira/browse/WICKET-2207--
Jeremy Thomerson
http://www.wickettraining.com