How can I find out which iTunes library my computer is using?

Question

I have a desktop Mac Mini at home that my wife uses and a MacBook Pro that I use at home and in the office.  I wanted to be able to access all the music we have on both machines from both machines, even when I am out and about and have no network connection for my MacBook Pro. So, I uploaded all the music we had on iTunes to Dropbox, and this now syncs on both computers.  So, whenever either of us adds music to iTunes, the songs are saved on both machines within the Music folder in Dropbox, which syncs in real time across both computers.  So far so good.
However, what I am finding is that, when either of us adds new music to our respective iTunes, it only shows on the computer on which it's been added.  So, within a matter of weeks, our computers no longer show the same music in our respective iTunes windows, even though the music is present on both machines in the synchronised Dropbox folder.
I realised that the computers must start using different iTunes library to each other when new songs are added to either machine.  So, I figured that, when we add music to one of the computers, if I pointed iTunes on the computer that has the less up-to-date music to the latest library that is being used by the computer with the more up-to-date music, this would ensure that both machines showed the same music in their repective iTunes windows.  The problem is that I cannot work out which iTunes library is being used by the computer with the more up-to-date music on it.  I know how to choose a different library when I open iTunes (hold down alt) but that doesn't help, because I all I want to do is to FIND OUT WHICH LIBRARY IS BEING USED BY ITUNES ON THE COMPUTER WITH THE MORE UP-TO-DATE MUSIC.  I simply can't find a way of getting iTunes to show me which library it is using, although this must be the simplest thing in the world. An additional issue is that I want to playlists we have created to appear on both machines - will that be the case if I point the less up-to-date iTunes (on my wife's Mac Mini) to the library of the more up-to-date iTunes (on my MacBook Pro), since my computer with the more up-to-date iTunes shows all the playlists, whereas my wife's doesn't?
So, can anyone help?  Plus if anyone knows of any software that can automatically ensure that two different Macs both use the same and most up-to-date iTunes library and therefore always show the lastest music collection, whichever machine the music has been added to, that would be fantastic.  Thanks.

Answer 1

You could have all the computers point to the same library but it can't be opened by more than one at any time.
No answer for knowing which library is in use other than selecting it at startup.  This question gets asked here occasionally but I don't think it is a high-demand feature since most people have just one library.  I guess you could put in an empty playlist with the library name so you have an identifier.