Jazz uses an optimizer to respond to an http request for a javascript file
with a single response that combines a bunch of javascript files. If you are
using the "experimental" version of firebug that supports the option of
Script->options "Show eval() options", and you have that setting enabled,
firebug makes an attempt to be able to debug the eval'ed sources. The
combined javascript response from jazz can be quite large, and can
apparently overwhelm the firebug implementation.

The symptoms will be that the http request in the firebug console window
will be a GET, and it will appear to throb for a long time. Your hard disk
will be completely busy. If you look at your firefox process using a tool
like Process Explorer on Windows, you will see that the virtual memory used
by the firefox browser grows dramatically, above 2 gigabytes.

You can see this happen by connecting to the jazz.net UI with "Show eval()
options" set to true. Navigate from the Jazz Home -> Bug Tracking, and
select the "Advanced Bug Search". This will generate an http request such
as:

GET
https://jazz.net/jazz/web/com.ibm.team.workitem.web/ui/internal/page/WorkItemPageView.js?ver=9590104955&loc=en-us&dep=CHCGC0DMDNDLDFDGDHDIDEDKDCDSDUB6B5CwDWDVDTDXDYDbDdDeDcDaDfDZDgDhDjDiDlDkDmDnDpDsDrDtCzATBdC4DuDqDoCADwDvDzDyDxD0D1D2D3D4D5D6D7DRD8DPDQD-EAECEBEECbCeCgCfCdEFEHEIEGEDEJELEKENEMEPEOEQERD_ETESEVEUEWEYEaEZEbDOEXCxEcEdEeEfEhEg
(313ms)

In some circumstances, firebug will eventually finish its analysis of the
eval'ed code, and will release a bunch of memory and you can proceed. This
can take a long time, so it is possible that it would generally succeed and
I am just not patient enough.