The 2.0+ versions are quite a bit different than the 1.5 version. There
already have been many complaints about the interface changes. Check
the archives.
Basically it boils down to firefox/iceweasel doesn't follow the linux
standards because it is designed as a windows program. One poster
pointed out that if the GNU/Linux version can place the configuration
options in a different place, it can adhere to standard in interface,
yet it doesn't. It seems we need to mass complain to the mozilla project.
Joe