Checkbox "Automatically detect safe locations and exclude them from virtualized" is checked by default, it means all downloads (in standard way) won't be virtualized. It also means, that some settings inside browsers won't be virtualized either (bookmarks, cookies, history ...). I think we'll split it into more checkboxes or rather we'll try to add more expert settings in new builds.
Add-on updates cannot be detected automatically, because when I've updated my three addons I saw a lot of internal files were modified (prefs.js, data files, ...). For now, you 'll need to run FF outside the sandbox and perform these "radical" changes there. I think we'll include a checkbox in expert settings which would allow to stop virtualizing for the entire FF profile (unchecked by default, because I guess it might be a security risk).
Thanks pk, i have to set an exclusion for addons like C:\Program Files\Mozilla Firefox\plugins\* ??
The right entry to exclude the entire FF profile is:
%AppData%\Mozilla\Firefox\Profiles\* (don't use Browse button, just copy&paste it there)