The environment uses various flags to inform you of the current status of a module.

+ This indicates that the module has a local compiler option overriding the global option.
- This indicates that if a build were to start right now this module will need to be compiled.
* This indicates that one or more modules in the project need this module, but the source file for the module could not be found. You can easily find the modules that are importing this module by selecting this module and using the Tools menu, List Clients menu item command.
+- This indicates that the module has both an option override and needs to be compiled.