When using the Jekins Recent Changes View to jump into the Polarion Web SVN Viewer, the user is asked for the login credentials during a redirect.
Trying to get back from Polarion to the Jenkins Recent Changes View by using the browser's back button fails at the Login-Dialog redirect. You cannot get past that by using a single click on the back button, instead you need to select the Jenkins Recent Changes View from the Back Button history by skipping the redirect entry.

This was working with an earlier version of Polarion and seems to have stopped with the 2011 version of Polarion.

We have reported the issue to Polarion and received the following answer:
"This problem is caused by the fact that you use internal url of the svn web client that is embedded in Polarion. You need either to use the Polarion portal url like e.g. http://almdemo.polarion.com/polarion/#/project/elibrary/repository/browser (in which case you will see the Polarion navigator around (and in fact you will need to press Back-arrow/space twice), or you can install a standalone version of the SVN Web Client (can be downloaded from http://community.polarion.org) and use links to this instance from Jenkins/Hudson."

So it seems as if the Polarion plugin is using the wrong URL into the Web Viewer.

HTTPFox Log File Excerpt:
1. Click on Jenkins/Hudson Project Link "Recent Changes"
00:23:26.513 0.053 588 293 GET 200 text/html http://JENKINS:8080/hudson/job/erknt/changes/4

2. + 3. Click on "Polarion WebClient" and Login to Polarion
00:23:31.234 0.188 580 416 GET 200 text/html https://POLARION/svnwebclient/revisionDetails.jsp?location=&rev=61498
00:23:31.500 0.148 695 260 POST 302 Redirect to: https://POLARION/polarion/;jsessionid=413285E2112EAC9B111B8876076D279B https://POLARION/polarion/j_security_check
00:23:31.738 0.096 667 2215 GET 200 text/html https://POLARION/polarion/;jsessionid=413285E2112EAC9B111B8876076D279B
00:23:35.196 0.050 990 237 POST 302 Redirect to: https://POLARION/polarion/login/redirector https://seu41.gdc-leinf01.t-systems.com/polarion/login/proxy
00:23:35.295 0.049 640 412 GET 200 text/html https://POLARION/polarion/login/redirector
00:23:35.397 0.118 724 237 POST 302 Redirect to: https://POLARION/svnwebclient/revisionDetails.jsp?location=&rev=61498 https://seu41.gdc-leinf01.tsystems.
com/polarion/j_security_check
00:23:35.577 0.226 702 2180 GET 200 text/html https://POLARION/svnwebclient/revisionDetails.jsp?location=&rev=61498

4. Back Button
00:23:38.628 0.044 688 (231) GET (Cache) text/html https://POLARION/polarion/login/redirector
00:23:38.754 0.070 772 608 POST 404 text/html https://POLARION/polarion/j_security_check