Description of problem:


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

Firefox 10.0.6-1.el5_8

How reproducible:
Every time. 

Steps to Reproduce:
1.Install RHEL5.8. 
2.Update Firefox to its latest version.
3.Open https://twitter.com/ (create account + log in)
4.Try to compose new tweet (blue square button on the right top corner). Or you can try replying to an existing tweet. 


Actual results:
When trying to create new tweet or replying to a tweet nothing happens. No errors in the Error Console. 

Expected results:
Window/pop-up will come up to create tweet or update existing one. 


Additional info:

Same Firefox version on RHEL5.8_x64 bit works.