Hi Guido,
The login page on Moodle.org works regardless of the location the user has come from because although it has the
URL the user was last at it doesn't know how to the use that to work out what the user was actually looking at. For some pages like viewing a category or viewing a course it could guess but other pages it would be practically impossible. Because of this it always runs in the system
context (the site level) and you get the system theme.
Within 1.9 it would be a very difficult job to change this and would require many many hours, and I don't think it would be truthfully feasible.
However in Moodle 2.0 every page the user can possibly enter on is required to set a context, this we could possibly use, we could pass it to all redirections to the login page to identify at least the general area the user is coming from making this possible.
That all being said there are still a lot of different variables that come into play, what if the user is coming from a different site (Moodle networking) or what if the user doesn't have
permission to view the page that they were coming from once they have logged in.
That is the technical side of it as I see it, the next bit is just my two cents.
Are you sure that this is what you want?
If users arrive at your site's
front page they are going to see your sites theme, this is
hopefully the theme that they likely will become familiar with first. Once they start exploring your site they may encounter category themes, course themes, and/or user themes.
I would think if you are really concerned about people not becoming familiar with your category themes you should perhaps consider using just one theme throughout the entire site, or if you really want to use different themes make sure the theme's you choose are similar (and certainly not radically different).
Usability wise, one look is the best to deal with.
I understand that people want to be able to set different theme's for different areas of there site, but I think that this can lead to a potential design disaster if they aren't careful in analysing the users of their site, and the differences that exist within those themes.
Certainly as of Moodle 2.0 unless the changes are major one theme should be used and
CSS + layout files should be used to alter the theme as required.
Hope this helps.
Cheers
Sam
