Searching a file in Source Control

You can search for files with Search -> Jazz Source Control -> Change Sets.
You may need to click into the changeset and locate the files you are looking for.
Because it is not straightforward, there are several RFEs available to improve this feature:

https://jazz.net/jazz/web/projects/Rational%20Team%20Concert#action=com.ibm.team.workitem.viewWorkItem&id=98963

https://jazz.net/jazz/web/projects/Rational%20Team%20Concert#action=com.ibm.team.workitem.viewWorkItem&id=102557

https://jazz.net/jazz/web/projects/Rational%20Team%20Concert#action=com.ibm.team.workitem.viewWorkItem&id=102509

You can comment on the RFE you are interested in and vote for it.
Thanks