Minor Description
In case wicket catches a runtime error it will redirect to an error page. In that case an url like
http://127.0.0.1:8080//url/test?param=bad_value
will be replaced by something like
http://127.0.0.1:8080/wicket/page?1
which is not very helpful (you won't be able to see that 'param' got a 'bad_value' in that case).
Also the user can not try to hit reload it the error is of temporary nature.
Additionally, after the session expires and the user hits reload on the url (and probably still hoping it get's better 
http://127.0.0.1:8080/wicket/page
you will give you an http error '404 - page not found' as the error page url is not bookmarkable.
Keeping the source url and not doing a redirect would be better:
- reload in the browser will work
- expires pages will not break the URL
patch is included.