I don't think we need to do a legacy application class. A lot of the methods from JApplication are already copied over into JApplicationTracker, so I'd just add whatever other application methods are needed there. Also, if we go the multi-application route, I'd like to make JApplicationTracker more of an abstract base class that our "site" and "admin" apps extend from (similar to the current JSite and JAdministrator).

9da662f is definitely what we need to do here for that switch.

Is the #__messages stuff needed (i.e. that closely tied in with one of the other admin components)?

The rest of it, I think you're on the right track with.

Take a look at ba1e706 - this is how I'd structure the application classes. I have a branch in my CMS fork where both applications are working on the new application class, so changing from JAdministrator to JApplicationAdministrator (for example) should be no issue.

Yes, I created the legacy application class only to avoid conflicts. It was not meant to stay.

As for the "multi application road" - I am also not quite sure if we need a separate administrator application. It was just easier to integrate com_users. It should also be possible to just move the code to the "site" application.

Making JApplicationTracker the base class and extend it with site- and admin classes also makes perfect sense.

As for the #__messages table: that was done to have less initial changes on com_users. I doubt that we will need mass mails (or user notes for that matter) in the tracker application. So they may, or may not, be removed in the process of refactoring - just thinking about backporting the work to the CMS ;)

As for your proposal: Yeah, libraries/tracker/application/site.php looks pretty cool - merge this please ;)

Once I get back to my computer, I'll merge it all in. Thanks for your work on this!

Oh, well i meant that you merge in your proposed changes :)

Or would it be easier if I do the modifications in this PR ?

I just need to merge the pr10 branch to master, which has this PR plus my commit.

Huh, I didn't noticed the pr10 branch - I actually wondered where the commit came from ;)

So I can merge the pr10 branch into mine and continue from here before merging to master ?

Well, this seems to have worked - git rocks :)

Just say when and I'll merge it :-)