Why isn GEF showing up in Eclipse?
After installing GEF by extracting it to the necessary directories, it may be necessary to accept the changes within Eclipse. This can be accomplished by going to Help->Software Updates->Manage Configuration and right-clicking on Eclipse Platform. Select “Detected Changes…” from the menu and click Finish to complete the installation. This is the most common cause of the install not showing up in the aforementioned Plug-in Details view.