Just to note... it seems this has been fixed in herd 5, which has an all new partitioning system for the installer. I guess we can close this bug. :)
-- Partitioning very confusing in Kubuntu install https://launchpad.net/bugs/87418 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs