Description of problem:
In search form I click on Fedora (Classification), Fedora (Product) and then the whole browser freezes. After few seconds this message appears:

'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.

Script: https://bugzilla.redhat.com/js/productform.js?1336993663:296'

it asks if I want to stop script or to continue. If I choose to stop, there are missing components (the list ends with about 's') and in 'Detailed bug information' isn't filled. If I choose to continue it is finished correctly - I can see all components and Versions and so.

The cpu usage is raised to 100% during this. This bug has been filled for 3.2 (bug 457843) and closed as NEXTRELEASE and ... no change.

Searching with this is very slow and annoying.

Version-Release number of selected component (if applicable):
4.2

How reproducible:
Always

Steps to Reproduce:
1. Go to Advanced search form and choose Fedora->Fedora
2. Wait
  
Actual results:
Firefox freezes for few seconds and warning message is shown.

Expected results:
There should be no freeze and no warning.

Additional info: