Last modified: 2008-07-02 09:07:32 UTC
I don't know how you got that behavior -- the link always pointed to "#", i.e. "the top of the page you are currently viewing".
The bahavior has now been changed in r36773 so that the [+] always links to the category. Hiding it in case JS is not enabled would only work by hiding it per default, and dynamically showing it if JS is enabled. Which may cause layout flickering, etc. Also, without the [+] and JS turned off, it would become a plain link, which may be confusing (tree? what tree?).
Marking this as fixed. If the new behavior seems wrong to you, please file a new bug report.