Restrictions of the eclipse workspace concept

There is an old paper nicely describing the problems and another with possible solutions (it also contains an analysis what other IDEs do).

Bugzilla entries:
- Allow editors to open files outside workspace
- Support logical model integration
- Problems with opening external files
- Allow a search to be done on external directories, outside of the workspace
- Rsource exclusion filters
The discussion about tne new eclipse virtual file system (EFS) in here: Provide more flexible workspaces. In 3.2 resources will probably be based on EFS.

Note: There might be problems with code that assumes IResource.getLocation().toFile() does not return null, if the resource is not a file!