I was able to add a file as-link to an project, as you can see in the image:



see the difference in the icon for files added as-link and files added as"normal"

but now don't remember how to add a file as link, or if this was because some add-in.
I've vs2010 installed in both desktop and laptop, the same of a few coworkers, and I like to have several general file (used as links) in different folders as the project folders.

anyway don't sure of as-link or normal are important in an project.
the only difference I've noted is that link files can't be edited when in debug.

basically I'm thinking in add as-link the files that are shared/used in several projects, as general modules or classes that have functions or subs intended to be as shared.

so the question mainly is
¿ how to add a file as-link ?