Fresh cauldron install, get to Summary, choose bootloader configuration. Choose "grub2-graphical" and the partition on which you just installed MGA (/). On the next panel, the "Default" dropdown does not include the root partition. The objective here is to create a self-contained partition which includes its own grub2 stuff and can be chainlinked to from an existing MBR bootloader. I remember reading a while back that the grub2 devs weren't fond of this at all, but there's no reason we shouldn't offer it if it works.
You're mistaken: - indeed, on the first screen you can choose the partition so that won't be offered again on the 2nd scree - on the second screen, you can choose the default menu entry to boot, not a partition
Status: NEW => RESOLVEDCC: (none) => thierry.vignaudResolution: (none) => INVALID
Hmm, that wasn't my experience. I had installed on /dev/sda1 and chose /dev/sda1 for the bootloader. drakx-install appears to have read through the legacy grub menu.lst from the MBR and created the dropdown list. Many of these entries included the device name in the menu entry name, e. g. /dev/sda2 or /dev/sda3. Some of them, which had the same names as existing legacy menu entries, did not. None of them included /dev/sda1. Are you saying that those entries without a device annotation were /dev/sda1 by default ?