Recently I took some time to rewrite the gedit-openfiles plug-in and also added one big feature. Before I get in to the details of the new feature I wanted to give a brief description of what the plug-in does.
gedit-openfiles uses the root of the file browser to index all the files in the working directory and sub directories. Doing this allows for quickly searching with in your project. The plug-in was designed to handle very large projects, I have personal tested it on a project with 4,000 files and it worked perfectly.

The new feature to the plugin is it now supports multiple windows. If you are working on a project in a gedit window and you open another window to work on a different project, when opening gedit-openfiles (ctrl+alt+o) in a window it will only search files specific to that window (screen cast demo below).
Gedit Open Files from Vitaly Babiy on Vimeo.
You can find the plug-in on github http://github.com/vbabiy/gedit-openfiles, enjoy!
