eGit add to index behvior

I used git for some time, and now I want to use eGit for Eclipse integration.

I have a question about operation "Add to index" behavior. Does it behave exactly like the git add command?

Let's consider the following example:

1. Make some changes to file (lets call it ver1).
2. Mark it and click "Add to index".
3. Make more changes in the same file (lets call it ver2).
4. Make commity.

Which version of file will be committed into repository? If "Add to index" behave analogical to git add it should be ver1. But will it be ver1 or ver2?

OK, because no one want to respond I made few experiments and it looks, that eGit Add to index behave analogical to git add.