The module is still there on my Linux64 Slicer3.5 build today, under the Modules drop down menu, Tractography, Editor, ROISelect.
Which OS are you using?

I am using a Linux64 and I just downloaded Slicer3.5-alpha-2009-06-01-linux-x86_64. Editor does not appear under Tractography and ROISelect is also missing from AllModules.

I checked the repository logs, and it turns out that the module was removed at the request of the developer, see the comment on revision 8999:
http://viewvc.slicer.org/viewcvs.cgi/trunk/Modules/Tractography/CMakeLists.txt?rev=8999&view=log
I'll point Lauren to this bug and see if she has a solution to propose. If you've got a version of slicer that you've built yourself you can just undo that change, adding in the line "Editor" to the subdirs command, and rebuild, as the code is still there.

From the developer:
I am working on a grant due Friday but I can look at this next week -- the
module did not work in slicer3 how was anyone using it? There is a module in
python that does work -- C-F knows about it, it was created by Demian. Could
you inform the user to use this module instead?

Waiting to hear from CF.

The PNL RAs are interested in this too. Please let me know about the python module, or what its status is in Slicer 3.

I talked to Demian, he's got some non distributable code that he can let me look at. It relies on MRML ROI List nodes, which I double checked are still in MRML, and can be passed to CLI's. Demian may be able to get permission to distribute his python module, update next week.

Is there any update on the availability of an ROI fiber tracking selection filter for 3.5? Thanks

We'll start by re-enabling the existing code and then see what issues are left (which things led Lauren to think it doesn't work correctly).

I just re-enabled this in the trunk, so it should start showing up in the nightly builds.

Closing. Slicer3 is not being developed anymore.