[Edited]
The [Choose Your Desktop] installation screen lists KDE above Gnome. But when you choose one of them and press next, the opposite desktop environment is listed on the [Package Group Selection] page. The respective [Details] buttons also list the wrong desktop environment packages.
When I selected Gnome (CYD page) and then KDE (PGS page), I ended up with Gnome being installed.
Now I'm trying KDE-then-Gnome, in the hope of getting the preferred KDE this time!
