ubuntu-22.04 Installer won't let me delete partition?

[Josef Wolf]

Hello all,

while installing, I want to re-partition the disk, so I choose the
"custom storage layout" option. On the next screen, I delete all the file
systems that I do not need, and finally I see this:


  To continue you need to: Mount a filesystem at /
                           Select a boot disk

  FILE SYSTEM SUMMARY
    No disks or partitions mounted.

  AVAILABLE DEVICES

    DEVICE                                             TYPE SIZE
  [ Micron_XXXXXXX                                     local disk 476.939G > ]
    partition 1 existing, unused ESP, already formatted as vfat     1.049G >
    partition 2 existing, already formatted as ext4, not mounted    2.000G >
    partition 3 existing, unused                                  473.887G >


Now, I would like to split partition 3 into separate partitions. So I select
"Delete" from the entry for partition 3.

Then I get this error message:

  Cannot delete a single partition from a device that already has partitions.

Ugh! Is this for real? I can not delete an unused partition? So I really need
to create a new partition table from scratch and loose data that might reside
on an existing partition?

Anybody can give some clue about this?

-- 
Josef Wolf
jw at raven.inka.de